Pretreatment of biodiesel feedstock

ABSTRACT

Process and steps for the production of biodiesel and/or glycerin from feedstock are provided.

BRIEF SUMMARY OF THE INVENTION

The present invention provides for a method to produce biodiesel and/orglycerin from biodiesel feedstock. The production of biodiesel and/orglycerin includes a pretreatment process, an esterification processand/or a transesterification process. The pretreatment process isemployed to separate from the biodiesel feedstock, solid particleshaving a diameter of greater than about 2 microns. The pretreatmentprocess can also be employed to separate from the biodiesel feedstock,impurities such as sulfur, phosphorous, phosphatides, gums, strerols,metals and/or other color bodies. When a biodiesel feedstock containsthese impurities and/or solid particles having a diameter of greaterthan about 2 microns, the pretreatment process can be employed toseparate them. A benefit of the pretreatment process is the ability tohandle biodiesel feedstock having high levels of gums, phosphorous,sterols, sulfur, and/or color contaminants. The pretreatment process cansignificantly reduce the phosphorous and sulfur levels to below about 10ppm in the treated feedstock. The pretreatment process can alsosignificantly reduce the levels of chlorophyll, color bodies, gums,phosphatides, gums, sterols, and/or metals (e.g., calcium, magnesium,iron, copper, sodium, and potassium) in the treated feedstock.

The esterification process is employed when the biodiesel feedstockcontains free fatty acids (FFAs). When the biodiesel feedstock containsFFAs, the esterification process can be employed to convert FFAs tobiodiesel. With reference to biodiesel, free fatty acids present in thefeedstock react with methanol in the presence of catalyst (and/or highheat and/or high pressure) to form biodiesel and water.

The transesterification process is employed when the biodiesel feedstockcontains triglycerides. When the biodiesel feedstock containstriglycerides, the transesterification process can be employed toconvert triglycerides to biodiesel and glycerin. With reference tobiodiesel, triglycerides present in the feedstock react with methanol inthe presence of catalyst (and/or high heat and/or high pressure) to formbiodiesel and glycerin.

Pretreatment

The present invention provides for a pretreatment of biodieselfeedstock. The process includes:

(a) filtering a biodiesel feedstock, thereby separating from thefeedstock solid particles having a diameter up to 2 microns, to providea filtrate and a retentate;

(b) separating at least one of moisture and water from the filtrate, toprovide a dried filtrate;

(c) distilling the dried filtrate, to provide a distillate and aresidue;

(d) distilling the distillate to provide a subsequent distillate andoptionally a subsequent residue; and;

(e) optionally repeating steps (c) and (d), one or more times, bydistilling the subsequent distillate, to obtain a final distillate.

Esterification

The present invention also provides for an esterification of biodieselfeedstock. The process includes:

(a) contacting (i) methanol, (ii) a solid heterogeneous esterificationcatalyst, and (iii) a biodiesel feedstock including free fatty acids,wherein the contacting is carried out under conditions suitable toprovide an esterification reaction product including biodiesel,methanol, water, and optionally free fatty acids;

(b) separating water and methanol from the esterification reactionproduct;

(c) contacting the esterification reaction product with (i) methanol and(iii) a solid heterogeneous esterification catalyst, wherein thecontacting is carried out under conditions suitable to provide asubsequent esterification reaction product including biodiesel,methanol, water and optionally free fatty acids; and

(d) optionally repeating steps (b) and (c) one or more times, to providean esterification reaction product including biodiesel;

wherein the methanol separated from the one or more esterificationreaction products is purified to a purity of at least about 99.9 wt. %,and is employed in a subsequent esterification.

Transesterification

The present invention also provides for a transesterification ofbiodiesel feedstock. The process includes:

(a) contacting at a temperature of less than 102° F. (38.89° C.) (i)methanol, (ii) a solid heterogeneous transesterification catalyst, and(iii) a biodiesel feedstock including triglycerides, wherein thecontacting is carried out under conditions suitable to provide abiodiesel, methanol, water, glycerin and optionally triglycerides;

(b) separating water, glycerin and methanol from the transesterificationreaction product;

(c) contacting the transesterification reaction product with (i)methanol and (ii) a solid heterogeneous transesterification catalyst,wherein the contacting is carried out under conditions suitable toprovide a subsequent transesterification reaction product includingbiodiesel, methanol, water, glycerin and optionally triglycerides; and

(d) optionally repeating steps (b) and (c) one or more times, to providea transesterification reaction product including biodiesel and glycerin;

wherein the methanol separated from the one or more transesterificationreaction products is purified to a purity of at least about 99.9 wt. %,and is employed in a subsequent transesterification.

Production of Biodiesel from Feedstock

The present invention also provides for the production of biodiesel fromfeedstock. The process includes:

(a) filtering a biodiesel feedstock, thereby separating from thefeedstock solid particles having a diameter up to 2 microns, to providea filtrate and a retentate;

(b) separating at least one of moisture and water from the filtrate, toprovide a dried filtrate;

(c) distilling the dried filtrate, to provide a distillate and aresidue;

(d) distilling the distillate to provide a subsequent distillate andoptionally a subsequent residue;

(e) optionally repeating steps (c) and (d), one or more times, bydistilling the subsequent distillate, to obtain a final distillate;

(f) passing final distillate through an ion exchange resin;

(g) contacting (i) methanol, (ii) a solid heterogeneous esterificationcatalyst, and (iii) the final distillate, wherein the contacting iscarried out under conditions suitable to provide esterification reactionproduct including biodiesel, methanol, water, and optionally free fattyacids;

(h) separating water and methanol from the esterification reactionproduct;

(i) contacting the esterification reaction product with (i) methanol and(ii) a solid heterogeneous esterification catalyst, wherein thecontacting is carried out under conditions suitable to provide asubsequent esterification reaction product including biodiesel,methanol, water and optionally free fatty acids;

(j) optionally repeating steps (h) and (i) one or more times, to providean esterification reaction product including biodiesel;

wherein the methanol separated from the one or more esterificationreaction products is purified to a purity of at least about 99.9 wt. %,and is employed in a subsequent esterification, transesterification, orcombination thereof;

(k) contacting at a temperature of less than 102° F. (38.89° C.) (i)methanol, (ii) a solid heterogeneous transesterification catalyst, and(iii) the esterification reaction product, wherein the contacting iscarried out under conditions suitable to provide a biodiesel, methanol,water, glycerin and optionally triglycerides;

(l) separating water, glycerin and methanol from the transesterificationreaction product;

(m) contacting the transesterification reaction product with (i)methanol and (ii) a solid heterogeneous transesterification catalyst,wherein the contacting is carried out under conditions suitable toprovide a subsequent transesterification reaction product includingbiodiesel, methanol, water, glycerin and optionally triglycerides; and

(n) optionally repeating steps (l) and (m) one or more times, to providea transesterification reaction product including biodiesel and glycerin;

wherein the methanol separated from the one or more transesterificationreaction products is purified to a purity of at least about 99.9 wt. %,and is employed in a subsequent esterification, transesterification, orcombination thereof;

(o) removing glycerin, water and methanol from the one or moretransesterification reaction products, to provide a mixture includingbiodiesel;

(p) distilling the methanol obtained from the one or moretransesterification reaction products, one or more times, to providemethanol having a purity of at least about 99 wt. %, and reusing thepurified methanol in a subsequent esterification, transesterification,or combination thereof; and

(q) distilling the biodiesel one or more times, to provide a purifiedbiodiesel.

Production of Glycerin from Feedstock

The present invention also provides for the production of glycerin fromfeedstock. The process includes:

(a) filtering a biodiesel feedstock, thereby removing from the feedstocksolid particles having, a diameter up to 2 microns, to provide afiltrate and a retentate;

(b) separating at least one of moisture and water from the filtrate, toprovide a dried filtrate;

(c) distilling the dried filtrate, to provide a distillate and aresidue;

(d) distilling the distillate to provide a subsequent distillate andoptionally a subsequent residue;

(e) optionally repeating steps (c) and (d), one or more times, bydistilling the subsequent distillate, to obtain a final distillate;

(f) passing final distillate through an on exchange resin;

(g) contacting (i) methanol, (ii) a solid heterogeneous esterificationcatalyst, and (iii) the final distillate, wherein the contacting iscarried out under conditions suitable to provide an esterificationreaction product including biodiesel, methanol, water, and optionallyfree fatty acids;

(h) separating water and methanol from the esterification reactionproduct;

(i) contacting the esterification reaction product with (i) methanol and(ii) a solid heterogeneous esterification catalyst, wherein thecontacting is carried out under conditions suitable to provide asubsequent esterification reaction product including biodiesel,methanol, water and optionally free fatty acids;

(j) optionally repeating steps (h) and (i) one or more times, to providean esterification reaction product including biodiesel;

wherein the methanol separated from the one or more esterificationreaction products is purified to a purity of at least about 99.9 wt. %,and is employed in a subsequent esterification, transesterification, orcombination thereof;

(k) contacting at a temperature of less than 102° F. (38.89° C.) (i)methanol, (ii) a solid heterogeneous transesterification catalyst, and(iii) the esterification reaction product, wherein the contacting iscarried out under conditions suitable to provide a biodiesel, methanol,water, glycerin and optionally triglycerides;

(l) separating water, glycerin and methanol from the transesterificationreaction product;

(m) contacting the transesterification reaction product with (i)methanol and (ii) a solid heterogeneous transesterification catalyst,wherein the contacting is carried out under conditions suitable toprovide a subsequent transesterification reaction product includingbiodiesel, methanol, water, glycerin and optionally triglycerides; and

(n) optionally repeating steps (l) and (m) one or more times, to providea transesterification reaction product including biodiesel and glycerin;

wherein the methanol separated from the one or more transesterificationreaction products is purified to a purity of at least about 99.9 wt. %,and is employed in a subsequent esterification, transesterification, orcombination thereof;

(o) separating, via distillation, glycerin from the one or moretransesterification reaction products; and

(p) distilling the glycerin, and passing through activated carbon, toprovide a purified glycerin.

Pretreatment, Esterification and Transesterification

The present invention also provides for the pretreatment, esterificationand transesterification of biodiesel feedstock. The process includes:

(a) filtering a biodiesel feedstock, thereby separating from thefeedstock solid particles having a diameter up to 2 microns, to providea filtrate and a retentate;

(b) separating at least one of moisture and water from the filtrate, toprovide a dried filtrate;

(c) distilling the dried filtrate, to provide a distillate and aresidue;

(d) distilling the distillate to provide a subsequent distillate andoptionally a subsequent residue;

(e) optionally repeating steps (c) and (d), one or more times, bydistilling the subsequent distillate, to obtain a final distillate;

(f) passing final distillate through an ion exchange resin;

(g) contacting (i) methanol, (ii) a solid heterogeneous esterificationcatalyst, and (iii) the final distillate, wherein the contacting iscarried out under conditions suitable to provide an esterificationreaction product including biodiesel, methanol, water, and optionallyfree fatty acids;

(h) separating water and methanol from the esterification reactionproduct;

(i) contacting the esterification reaction product with (i) methanol and(ii) a solid heterogeneous esterification catalyst, wherein thecontacting is carried out under conditions suitable to provide asubsequent esterification reaction product including biodiesel,methanol, water and optionally free fatty acids;

(j) optionally repeating steps (h) and (i) one or more times, to providean esterification reaction product including biodiesel;

wherein the methanol separated from the one or more esterificationreaction products is purified to a purity of at least about 993 wt %,and is employed in a subsequent esterification, transesterification, orcombination thereof;

(k) contacting at a temperature of less than 102° F. (38.83° C.) (i)methanol, (ii) a solid heterogeneous transesterification catalyst, and(iii) the esterification reaction product, wherein the contacting iscarried out under conditions suitable to provide a biodiesel, methanol,water, glycerin and optionally triglycerides;

(l) separating water, glycerin and methanol from the transesterificationreaction product;

(m) contacting the transesterification reaction product with (i)methanol and (ii) a solid heterogeneous transesterification catalyst,wherein the contacting is carried out under conditions suitable toprovide a subsequent transesterification reaction product includingbiodiesel, methanol, water, glycerin and optionally triglycerides; and

(n) optionally repeating steps (l) and (m) one or more times, to providea transesterification reaction product including biodiesel and glycerin;

wherein the methanol separated from the one or more transesterificationreaction products is purified to a purity of at least about 993 wt %,and is employed in a subsequent esterification, transesterification, orcombination thereof.

ADVANTAGES

In specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin that does notemploy the introduction of water. In further specific embodiments,advantages of the invention provide for a pretreatment process that canemploy a waterless wash process.

In specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin that does notemploy the introduction of a toxic mineral acid (e.g., phosphoric acid,sulfuric acid, hydrochloric acid, citric acid, or a combinationthereof). Specifically, the esterification process can be carried out inthe absence of a toxic mineral acid. The use of acids often lead tostrict regulations, disposal of waste, yield loss, incomplete removal ofimpurities (e.g., cannot always separate sulfur, polymerizedtriglycerides, dimmers, trimers and sterols), and additional safetymeasures.

For example, traditional sulfuric acid based esterification technologiescan employ feedstock with a free fatty acid content of up to about 10-12wt. %. In contrast, in specific embodiments of the present inventionthat do not employ the introduction of a toxic mineral acid, a feedstockwith as free fatty acid content of up to 100 wt. % can be employed.

For example, traditional sulfuric acid based esterification technologiestypically have yield below about 90 wt. %, due to incomplete conversion.In contrast, in specific embodiments of the present invention that donot employ the introduction of a toxic mineral acid, conversions ofabout 99 wt. %, and higher, are typically achieved, in specificembodiments, advantages of the invention provide for a process thatreuses reagent, in a safe and renewable manner. Specifically, each ofthe esterification and transesterification processes can independentlyreuse and purify the methanol, e.g., by distillation. This can lower theoverall operating cost, lower the carbon footprint, and avoids the timeand costs associated with any reagent disposal.

In specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin that emitslittle or no discharge into the atmosphere. Additionally, in specificembodiments, advantages of the invention provide for a process for theproduction of biodiesel and/or glycerin that does not include thegeneration of toxic waste, that would otherwise be disposed of, e.g., ina land-fill.

In specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin that arehigh-grade. In further specific embodiments, the biodiesel and/orglycerin produced from the methods described herein are products thatmeet or exceed stringent regulatory requirements (e.g., ASTM D6751standards). For example, glycerin can be obtained in a 99.7% puritytechnical grade, in further specific embodiments, advantages of theinvention provide for a process for the production of biodiesel and/orglycerin that include one or more impurities in the amounts illustratedin Table A. In further specific embodiments, advantages of the inventionprovide for a process for the production of biodiesel and/or glycerinthat include each of the impurities in the amounts illustrated in TableA.

In specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin, whereinspecific steps of the process are driven to completion (or nearcompletion) by the removal or separation of side-product(s) from thecrude reaction product, and subjecting the purified crude reactionproduct to that same process again. This respective process can becarried out until a minimal requisite amount of side-product isachieved.

For example, in an esterification process, biodiesel feedstock,catalyst, and methanol are subject to esterifying conditions, such thatfree fatty acids (FFA) present in the biodiesel feedstock areesterified, to produce a crude reaction product that includes biodiesel,water, methanol, triglycerides and unreacted free fatty acids. One wayto assist in driving the esterification reaction to completion iscarried out by removing or separating (e.g., via distillation) water andmethanol (as a mixture) from the crude reaction product to provide apurified crude reaction product that includes biodiesel, triglycerides,and free fatty acids. This crude reaction product can be subject toesterifying conditions to convert at least a portion of the free fattyacids present therein to triglycerides. This repeated esterificationprocess can be carried out until the amount of free fatty acids obtainedin an esterifying process is below a requisite amount (e.g., below about5 wt. %).

For example, in a transesterification process, biodiesel feedstock,catalyst, and methanol are subject to transesterifying conditions, suchthat triglycerides present in the biodiesel feedstock aretransesterified, to produce a crude reaction product that includesbiodiesel, water, glycerin, methanol, and unreacted triglycerides. Oneway to assist in driving the transesterification reaction to completionis carried out by removing or separating (e.g., via distillation) water,glycerin, and methanol (as a mixture) from the crude reaction product toprovide a purified crude reaction product that includes biodiesel andtriglycerides. This crude reaction product can be subject totransesterifying conditions to convert at least a portion of thetriglycerides present therein to biodiesel. This repeatedtransesterification process can be carried out until the amount oftriglycerides obtained in a transesterifying process is below arequisite amount (e.g., below about 5 wt. %).

In specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin, whereinspecific steps of the process are driven to completion (or nearcompletion) by employing a molar excess of reagent. For example, each ofthe transesterification and esterification processes can independentlyemploy a molar excess of the reagent methanol.

In specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin, wherein a solidcatalyst is employed in the esterification process, and free fatty acidsare converted to triglycerides yields of about 99.8%, and higher.

In specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin, wherein a solidcatalyst is employed in the transesterification process, andtriglycerides are converted to biodiesel in yields of about 99.8%, andhigher.

In specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin, wherein arelatively wide-variety of inexpensive and low-grade feedstock can beemployed, that would otherwise be considered waste and disposed of,e.g., in a land-fill. Such low-grade feedstock includes, e.g., browngrease, trap grease, and high free fatty acid based grease used cookingoil and animal fats, such as tallow, pork fat, poultry fat, lard, andchoice white grease.

For example, in specific embodiments, advantages of the inventionprovide for a process for the production of biodiesel and/or glycerin,wherein the feedstock can include relatively high amounts of impurities(e.g., between about 15 ppm and 1000 ppm sulfur, up to 300 ppmphosphorus, up to 3 wt. % unsaponifiables and phospholipids, up to 0.5wt. % polymerized triglycerides, up to 0.5% dimers and trimers,phytosterols, sitosterols, cholesterol, and/or sterol glucosides). Infurther specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin, that employs alow-grade biodiesel feedstock having one or more impurities in theamounts as illustrated in Table A herein. In further specificembodiments, advantages of the invention provide for a process for theproduction of biodiesel and/or glycerin, that employs a low-gradebiodiesel feedstock having each of the impurities in the amounts asillustrated in Table A herein.

In specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin, wherein abiodiesel feedstock that includes up to about 100 wt. % free fatty acids(FFAs) can be employed.

In specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin in a relativelycost-effective manner, employing relatively low energy consumption.Specially, the transesterification process can be carried out at atemperature of about 95° F.

In specific embodiments, advantages of the invention provide for aprocess for the production of commercial or industrial amounts ofbiodiesel and/or glycerin (e.g., at least about 1,000 gallons) in arelatively short period of time (e.g., within about 48 hours).

In specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin, wherein any oneor more of the steps of the production are carried out in a continuousfashion. In further specific embodiments, advantages of the inventionprovide for a process for the production of biodiesel and/or glycerin,wherein each of the steps of the production is carried out in acontinuous fashion.

In specific embodiments, advantages of the invention provide for aprocess for the production of biodiesel and/or glycerin, wherein theproduction results in a relatively low carbon footprint.

In specific embodiments wherein the esterification employs a solid,heterogeneous esterification catalyst, advantages of the inventionprovide for a process that produces little or no soap. As such, anysubsequent glycerin separation becomes relatively easier (in the absenceof soaps and salts).

Traditional transesterification technologies sometimes employ sodiummethylate, which leads to saponification issues, which in turn affectsbiodiesel-glycerin separation and lowers the glycerin purity, leading toa higher acid number and yield loss. Use of acids to neutralize andsplit the soaps typically leads to higher operating cost and disposalissues. Slower kinetics lead to larger footprint and restricts the usefeedstocks higher in FFA, which are typically significantly lessexpensive than virgin oils. In contrast, in specific embodiments of thepresent invention that employ a solid, heterogeneous transesterificationcatalyst, advantages of the invention provide for a transesterificationthat can be carried out at lower temperatures (e.g., about 95° F.), theelimination of (or the ability to avoid the use of) sodium methylate,relatively short conversion times (e.g., 30-45 minutes retention time ateach reactor stage), relatively high yields (e.g., above about 99 wt. %conversion of triglycerides to biodiesel and glycerin), the ability toemploy a wide-range of biodiesel feedstocks, and/or with the ability toobtain the desired product (e.g., biodiesel and/or glycerin) in arelatively high yield (e.g., above about 99.5 wt. %) and high purity(e.g., above about 95 wt. %).

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention may be best understood by referring to thefollowing description and accompanying drawings which illustrate suchembodiments. The numbering scheme for the Figures included herein aresuch that the leading number for a given reference number in a Figure isassociated with the number of the Figure. Reference numbers are the samefor those elements that are the same across different Figures. Forexample, a process flow diagram depicting esterifying (206) can belocated in FIG. 2. However, reference numbers are the same for thoseelements that are the same across different Figures. In the drawings:

FIG. 1 illustrates a process flow diagram for the pretreatment ofbiodiesel feedstock.

FIG. 2 illustrates a process flow diagram for the esterification of freefatty acids.

FIG. 3 illustrates a process flow diagram for the transesterification oftriglycerides.

FIG. 4 illustrates a process flow diagram for the pretreatment ofbiodiesel feedstock.

FIG. 5 illustrates a process flow diagram for the esterification of freefatty acids.

FIG. 6 illustrates a process flow diagram for the transesterification oftriglycerides.

DETAILED DESCRIPTION

The following detailed description includes embodiments and examples, inwhich the invention may be practiced. These embodiments and examples aredescribed in enough detail to enable those skilled in the art topractice the invention. The embodiments may be combined, otherembodiments may be utilized, or structural, and logical changes may bemade without departing from the scope of the present invention. Thefollowing detailed description is, therefore, not to be taken in alimiting sense, and the scope of the present invention is defined by theappended claims and their equivalents.

Reference will now be made in detail to certain claims of the presentinvention, examples of which are illustrated herein. While the presentinvention will be described in conjunction with the enumerated claims,it will be understood that they are not intended to limit the claimedsubject matter. On the contrary, the present invention is intended tocover all alternatives, modifications, and equivalents, which may beincluded within the scope of the present invention as defined by theclaims.

References in the specification to “one embodiment”, “an embodiment”,“an example embodiment”, etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

The presently disclosed subject matter relates to methods for producingbiodiesel and/or glycerin. When describing the methods for producingbiodiesel and/or glycerin, the following terms have the followingmeanings, unless otherwise indicated.

DEFINITIONS

As used herein, “wt. %” refers to weight percent or weight percentage.

As used herein, “filtering” refers to a mechanical or physical operationwhich is used for the separation of solids from fluids (liquids orgases) by interposing a medium through which the fluid (and relativelysmall solid particles) can readily pass.

As used herein, “biodiesel feedstock” refers to those starting materialsthat are used to make biofuels. Biofuels are fuels derived frombiological materials such as, e.g., plant oils and animal fats. Examplesof “biodiesel feedstocks” are elaborated below in the section “BiodieselFeedstocks.” Typically, the biodiesel feedstock will include free fattyacids and triglycerides.

As used herein, “free fatty acids” refer to nonesterified fatty acids.Free fatty acids are sometimes present in biodiesel feedstock.

As used herein, “solid particles” refers to relatively small objectshaving a precise physical boundary in all directions. A particle ischaracterized by its volume and interfacial surface in contact with itsenvironment. Solid particles have a definite shape.

As used herein, “diameter” refers to the maximum distance of a straightline that passes through the center of a particle and whose end pointsare on the surface of the particle.

As used herein, “filtrate” refers to the liquid produced after filteringa suspension of a solid in a liquid.

As used herein, “dried filtrate” refers to the removal or separation ofmoisture and/or water from the filtrate.

As used herein, “retentate” refers to the solid remaining in the filterafter filtering a suspension of a solid in a liquid.

As used herein, “moisture” refers to the presence of a liquid,especially water, often in trace amounts. Moisture may be found, forexample, in the air (humidity), in feedstock, and in various commercialproducts.

As used herein, “water” refers to a chemical substance with the chemicalformula H₂O.

As used herein, “distilling” refers to a method of separating a mixturebased on the difference in volatilities of components in a boilingliquid mixture.

As used herein, “distillate” refers to the concentrated or purifiedliquid, called the distillate that is collected as a result ofdistillation.

As used herein, “residue” refers to the portion of the mixture thatremains after distillation and which is the least volatile material thathas not been separately captured as a condensed vapor.

As used herein, “fats” refers to a wide group of compounds that aregenerally soluble in organic solvents and generally insoluble in water.Chemically, fats are triglycerides, triesters of glycerol and any ofseveral fatty acids. Fats may be either solid or liquid at roomtemperature, depending on their structure and composition. Specifically,“fats” is usually used to refer to fats that are solids at normal roomtemperature

As used herein, “oils” refer to fats that are liquids at normal roomtemperature, while “fats” is usually used to refer to fats that aresolids at normal room temperature.

As used herein, “edible oils” refers to a liquid fat that is capable ofbeing eaten as a food or food accessory.

As used herein, “inedible oils” refers to refers to a liquid fat that isnot capable of being eaten as a food or food accessory.

As used herein, “grease” refers to soft or melted animal fat, especiallyafter rendering.

As used herein, “brown grease” refers to waste vegetable oil, animalfat, grease, etc. that is recovered from a waste water component calleda grease trap. It is the grease that is removed from wastewater sentdown a sink drain. Brown grease is contaminated grease.

As used herein, “trap grease” refers to grease obtained from a plumbingdevices designed to intercept most greases and solids before they entera wastewater disposal system

As used herein, “used cooking oil” refers to plant, animal, or syntheticcooking oil that has been previously used in frying, baking and othertypes of cooking.

As used herein, “used cooking fat” refers to plant, animal or syntheticfat that has been used in frying, baking, and other types of cooking

As used herein, “animal fat” refers to solid lipid materials derivedfrom animals. Chemically, animal fats are composed of triglycerides.

As used herein, “animal grease” refers to animal fat used or produced incooking. It is often soft or melted.

As used herein, “fatty acid distillate” refers to the fatty acidsobtained by distillation. Fatty acids generated during fat splitting ormethyl esters from a transesterification process are generally purifiedby distillation to separate the fatty acids into groups according totheir chain lengths.

As used herein, “tallow” refers to a rendered form of beef or muttonfat.

As used herein, “pork fat” refers to fat from a pig.

As used herein, “poultry fat” refers to fat obtained (usually as aby-product) from poultry rendering and processing.

As used herein, “lard” refers to pig fat in both its rendered andunrendered form.

As used herein, “choice white grease” refers to a specific grade ofmostly pork fat defined by hardness, color, fatty acid content,moisture, insolubles, unsaponifiables, and free fatty acids.

As used herein, “algae oil” refers to the lipid or oily part of thealgae biomass.

As used herein, “crude vegetable oils” refers to the unrefined andunprocessed oil produced from vegetables—and how it is found in thenatural vegetable oil state when it is first extracted from thevegetable, whether the vegetable oil comes from corn, soybeans, oilpalm, jatropha, cottonseed, etc. To make the crude vegetable oil readyfor use, it must undergo further processing and refining to take it fromits crude form to a “refined vegetable oil” state.

As used herein, “soybean oil” refers to a vegetable oil extracted fromthe seeds of the soybean (Glycine max).

As used herein, “corn oil” refers to oil extracted from the germ of corn(maize).

As used herein, “coffee oil” refers to a volatile, oily substancedeveloped in the coffee bean upon roasting that gives coffee itsessence.

As used herein, “hemp oil” or “hempseed oil” refers to the oil obtainedby pressing hemp seeds. Hempseed oil is manufactured from varieties ofCannabis sativa that do not contain significant amounts oftetrahydrocannabinol (THC).

As used herein, “linseed oil” (also known as flaxseed oil) refers tocolorless to yellowish oil obtained from the dried ripe seeds of theflax plant (Linum usitatissimum, Linaceae).

As used herein, “rice bran oil” (also known as rice bran extract) refersto the oil extracted from the germ and inner husk of rice.

As used herein, “jojoba oil” refers to the liquid wax produced in theseed of the jojoba (Simmondsia chinensis) plant.

As used herein, “tall oil” (also called “liquid rosin” or tallol) refersto a viscous yellow-black odorous liquid obtained as a by-product of theKraft process of wood pulp manufacture when pulping mainly coniferoustrees.

As used herein, “mustard oil” refers to any of three different oils thatare made from mustard seeds: a fatty vegetable oil resulting frompressing the seeds; an essential oil resulting from grinding the seeds,mixing them with water, and extracting the resulting volatile oil bydistillation; and an oil made by infusing mustard seed extract intoanother vegetable oil, such as soybean oil. The pungency of mustard oilis due to the presence of allyl isothiocyanate.

As used herein, “DDG” refers to non-starch components of the corn kernelthat has undergone dewatering and dehydration. This by-product is soldas a commercial feed ingredient called DDG.

As used herein, “distillers grain oil” or “DDG corn oil” refers to thecorn oil that is present in DGG. It can be obtained by extraction fromDGG.

As used herein, “Jatropha oil” refers to the oil obtained from thecrushed seeds of Jatropha plants. Jatropha is a genus of floweringplants in the spurge family, Euphorbiaceae.

As used herein, “camellia oil” (also known as tea oil, camellia oil, ortsubaki oil) refers to an edible, pale amber-green fixed oil with asweet, herbal aroma. It is cold-pressed mainly from the seeds ofCamellia oleifera but also from Camellia sinensis, Camellia japonica andCamellia sasanqua.

As used herein, “rapeseed oil” also known as rape, oilseed rape, rapa,rappi, rapeseed) and, in the case of one particular group of cultivars,canola, refers to the oil derived from the seeds of the rapeseed plant,members of the family Brassicaceae.

As used herein, “canola oil” refers to the oil derived from the seeds ofa cultivar of either Rapeseed (Brassica napus L.) or field mustard(Brassica campestris L. or Brassica Rapa var.).

As used herein, “moring a oil” (also known as Ben oil) refers to the oilobtained by pressing the seeds of the Moring a Oilefera Tree.

As used herein, “pongamia oil” refers to the oil derived from the seedsof the Millettia pinnata tree. Millettia pinnata, also known as Pongamiaglabra, is common throughout Asia and thus has many different names indifferent languages, many of which have come to be used in English todescribe the seed oil derived from M. pinnata; Honge is the Kannada wordfor this tree. Other names for this oil include Karanja oil (fromHindi), Pungai oil (from Tamil), Honge oil (from the Kannada word forthe tree), and Pongamia oil.

As used herein, “sunflower oil” refers to the non-volatile oilcompressed from sunflower (Helianthus annuus) seeds

As used herein, “safflower oil” refers to a vegetable oil extracted fromthe seeds of the safflower plant (Carthamus tinctorius L).

As used herein, “crude palm oil” refers to the pre-purified oil that isextracted from the palm nut kernel. It contains non-glyceride componentssuch as trace metals, kernel shell pieces and products of oxidation.Purification removes or separates these components and makes the palmoil edible and sellable.

As used herein, “palm kernel oil” refers to an edible plant oil derivedfrom the kernel of the oil palm Elaeis guineensis. It is a highlysaturated vegetable fat containing the 16-carbon saturated fatty acidpalmitic acid.

As used herein, “palm fatty acid distillate” refers to a by-product ofthe crude palm oil refinery plant. The main components of Palm FattyAcid Distillate (PFAD) are the free fatty acids, oleic, stearic, andpalmitic.

As used herein, “palm sludge oil” refers to the fibers remaining afterthe palm fruit has been pressed to extract all the oil. It is alsocalled “the slurry.”

As used herein, “coconut oil” refers to an edible oil extracted from thekernel or meat of matured coconuts harvested from the coconut palm(Cocos nucifera).

As used herein, “filter” refers to a material that has very tiny holesand is used to separate out solid particles contained in a liquid or gasthat is passed through it. It also refers to the action of passing amaterial through a filter.

As used herein, “multiple” refers to comprising, consisting of,including, containing, or involving more than one.

As used herein, “porosity” refers to the property of a material havingmany pores or other small spaces that can hold a gas or liquid or allowit to pass through.

As used herein, “mesh size” refers to is the number of openings perlinear inch of mesh. Mesh materials are often used to determine theparticle size distribution of a granular material or to separate orfilter out particles by size. One well-known mesh series is the TylerEquivalent created by the W.S. Tyler screening company. Tyler mesh sizeis the number of openings per (linear) inch of mesh. The higher meshnumber the small the spaces between the mesh wires.

As used herein, “recycling” refers to the processing of reusing excessstarting material, excess solvent, and/or excess reagent that isrecovered, e.g., in a reaction product. For example, in each of theesterification and transesterification reactions described herein,methanol is employed as a reagent. When present in a stoichiometricexcess (e.g., 1.25 molar equivalent), methanol will typically be presentin the reaction product. This methanol can be separated from thereaction product, isolated and purified. The purified methanol can thenbe reused (or recycled) in a subsequent esterification and/ortransesterification reaction. The recycling of materials (e.g.,methanol), can lower the use of toxic chemicals, can prevent the wasteof potentially useful materials, can reduce the consumption of fresh rawmaterials, can reduce energy usage, can reduce air pollution (fromincineration) and water pollution (from land filling) by reducing theneed for “conventional” waste disposal, and/or can lower greenhouse gasemissions as compared to virgin production.

As used herein, “reflux ratio” refers to the ratio of parts condensatereturned to heating flask to parts condensate taken off to thecollection flask when separating two compounds by distillation.

As used herein, “non-toxic” refers to a material that is not poisonous,harmful, or otherwise destructive to an organism upon exposure.

As used herein, “continuously” refers to an event that is uninterruptedin time; without cessation.

As used herein, “continuously distilling” refers to form ofdistillation. It is an ongoing separation in which a mixture iscontinuously (without interruption) fed into the process and separatedfractions are removed continuously as output streams.

As used herein, “single stage distillation column” refers to a type ofdistillation in which only one stage is provided in which liquids boiland vapors condense. Single stage columns are often used to providecoarse separation of components with widely different boiling points.

As used herein, “multi-stage distillation column” refers to a type ofdistillation column in which successive stages are provided in whichliquids boil and the vapors from the stage above condense and in whichequilibrium between the two streams, liquid and vapor, is attained.

As used herein, “vacuum,” refers to a region of space having extremelylow gas pressure relative to surrounding pressure.

As used herein, “in vacuum,” or “under vacuum” refers to an extremelylow gas pressure, relative to surrounding pressure.

As used herein, “qualitative nature of impurities” refers to the kindsof impurities present.

As used herein, “quantitative nature of impurities” refers to the amountof impurities present.

As used herein, “adsorbent” refers to a material on which on which atomsor molecules move from a bulk phase (that is, solid, liquid, or gas)onto a solid or liquid surface (the adsorbant). An example ispurification by adsorption where impurities are filtered from liquids orgases by their adsorption onto the surface of a high-surface-area solidsuch as activated charcoal. Ambersep™ BD19 purification resin is anexample of an exchange resin that is an adsorbant.”

As used herein, “separated” or “separating” refers to the isolation ofat least one material from a mixture of materials, or the setting orkeeping apart of materials.

As used herein, “purifying” refers to the process of removing orseparating impurities from a material.

As used herein, “subsequently distilled” refers to distilling a materialafter first performing or treating a material in a prescribed manner.

As used herein, “subsequent distillate” refers to the concentrated orpurified liquid (i.e., distillate) obtained by redistilling a previousdistillate.

As used herein, “residue” refers to the portion of the mixture thatremains after distillation and which is the least volatile residue thathas not been separately captured as a condensed vapor.

As used herein, “subsequent residue” refers to the portion of themixture that remains (i.e., the residue) that remains after redistillinga previous distillate.

As used herein, “stored” or “storing” refers to placing or leaving amaterial in a location for preservation, later use, or disposal.

As used herein, “contacting” refers to placing two materials together ortouching, such as objects or surfaces.

As used herein, “methanol” refers to the compound CH₃OH. Methanol isalso known as methyl alcohol, wood alcohol, wood naphtha or woodspirits.

As used herein, “solid heterogeneous catalyst” refers to a catalyst thatis in a different phase than the reactants. For example the catalyst maybe a solid and the reactants may be a liquid. Amberlyst™ BD20 is anexample of a heterogeneous esterification catalyst.

As used herein, “esterifying” refers to the process of forming an ester.This process typically involves treating a carboxylic acid with analcohol in the presence of a dehydrating agent. An esterificationreaction is shown below.RCO₂H+R′OH→RCO₂R′+H₂OWhen the biodiesel feedstock includes free fatty acids, those free fattyacids can be esterified (e.g., with methanol and esterificationcatalyst, under suitable conditions), to provide biodiesel as thedesired product, and water as the by-product.

As used herein, “toxic mineral acid” refers to a mineral acid that ispoisonous, harmful, corrosive, or otherwise destructive to an organismupon exposure. Mineral acids are inorganic acids derived from one ormore inorganic compounds. All mineral acids form hydrogen ions and theconjugate base ions when dissolved in water. Examples of toxic mineralacids are sulfuric acid, nitric acid, hydrochloric, and nitric acid.

As used herein, “phosphoric acid” also known as orthophosphoric acid orphosphoric (V) acid, refers to a mineral (inorganic) acid having thechemical formula H₃PO₄.

As used herein, “sulfuric acid” refers to a highly corrosive strongmineral acid with the molecular formula H₂SO₄.

As used herein, “hydrochloric acid” refers to a clear colorless solutionof hydrogen chloride (HCl) in water. It is a highly corrosive, strongmineral acid.

As used herein, “citric acid” refers to a weak organic acid having theformula:

As used herein, “conversion” refers to the action of a chemicalreaction, e.g. the conversion of molecule A to molecule B. Examplesinclude the conversion of free fatty acids to their methyl ester.

As used herein, “soap” refers to the salt of a fatty acid.

As used herein, “salt product” refers to ionic compounds produced thatresult from the neutralization reaction of an acid and a base. Examplesinclude the sodium salts of fatty acids.

As used herein, “by-product” refers to a material produced usually in anindustrial or biological process in addition to the principal product.

As used herein, “side-product” refers to a product from a manufacturingprocess that is not considered the principal material, e.g., is theminor product.

As used herein, “standard temperature” refers to 273.15° K (0° Celsius).

As used herein, “standard pressure” refers to 1 atm pressure.

As used herein “standard ambient temperature and pressure” refers to293.15 K (25° Celsius) and 1 atm pressure.

As used herein, “premixed” refers to materials that are mixed or blendedfrom two or more ingredients or elements before being marketed, used, ormixed further.

As used herein, “ion exchange resin” or “ion exchange polymer” refers toan insoluble matrix (or support structure) normally in the form of small(e.g., 1-2 mm diameter) beads, usually white or yellowish, fabricatedfrom an organic polymer substrate. Ion exchange resins have a highlydeveloped structure of pores on the surface of which are sites witheasily trapped and released ions. The trapping of ions takes place onlywith simultaneous releasing of other ions; thus the process is calledion-exchange. There are multiple different types of ion-exchange resinwhich are fabricated to selectively prefer one or several differenttypes of ions.

As used herein, “Ambersep™ BD19” refers to an ion exchange resin thatincludes specific inert polymer beads and adsorbent. The ion exchangeresin can effectively remove or separate unwanted components from highfatty acid feedstocks, prior to esterification, and can improve theoperability of the downstream biodiesel production process. TheAmbersep™ BD19 purification technology can replace traditional oildegumming processes. The ion exchange resin can be employed in thepretreatment process, to extend the life of the Amberlyst™ BD20esterification catalyst (employed in the subsequent esterificationprocess). Even the smallest traces of soap, catalyst, and glycerolshould be removed from crude biodiesel in order to meet stringent newinternational quality specifications. The ion exchange resin improvesoperability of downstream manufacturing processes by removing orseparating chemical and physical foulants (e.g., cations, proteins,phospholipids, etc.). The ion exchange resin also helps preventpotential side reactions caused by unwanted components. The Ambersep™BD19 ion exchange resin is commercially available from Rohm and HaasCompany (Philadelphia, Pa.).

As used herein, “straight, flow-through 2 stage guard bed column reactorin series” refers to the use for example of two catalyst beds, one afterthe other. In the first stage, the first bed, known as the guard bed,contains a low-cost catalyst to remove or react with most of theimpurities. In the second stage, a second more expensive bed is used toremove or separate the remaining impurities.

As used herein, “Amberlyst™ BD20 solid catalyst” refers to a solid,heterogeneous polymeric esterification catalyst, for the conversion ofhigh free fatty acid (FFA) feedstock materials into valuable biodiesel.The solid catalyst is useful with, e.g., crude vegetable oils, animalfats, greases, fatty acid distillate, and recycled materials with an FFArange from 0.5 to 100%. Use of the solid catalyst can lower feedstockcost, increase process flexibility, increase biodiesel and/or glycerinyield, and improves biodiesel and/or glycerin purity. Amberlyst™ BD20solid, heterogeneous catalyst is commercially available from DowChemical (Midland, Mich.).

As used herein, “stoichiometric excess” refers to an excess of at leastone reagent or reactant over that which is the optimum amount ofreagents to completely form the product. A stoichiometric excess of areagent can be used to drive a reaction to completion.

As used herein, “molar excess” refers to an excess in the molar amountof at least one reagent or reactant over the number of moles of theoptimum moles of reagents to completely form the product.

As used herein, “flash column” refers to a distillation column used inflash vaporization. Flash vaporization is a process in which acontinuous liquid-mixture feed stream is partly vaporized in a column orvessel, with continuous withdrawal of vapor and liquid portions, thevapor and liquid in equilibrium. It is also known as continuousequilibrium vaporization; equilibrium distillation; flash distillation;and simple continuous distillation.

As used herein, “demister pads” refers to devices a fitted to vaporliquid separator vessels to enhance the removal of liquid dropletsentrained in a vapor stream. Demisters may be a mesh type coalescer,vane pack or other structure intended to aggregate the mist intodroplets that are heavy enough to separate from the vapor stream.

As used herein, “un-reacted” refers to the portion of starting materialsin a chemical reaction that do not combine.

As used herein, “subsequent” refers to something later in time or orderthan something else. Synonyms are following, and succeeding.

As used herein, “first stage reactor” refers to a reactor or vessel inwhich an initial reaction or processing occurs. For example, with anesterification, some of the free fatty acids and methanol is convertedto biodiesel and water in a 1^(st) stage esterification reactor.

As used herein, “second stage reactor” refers to a reactor or vessel inwhich a reaction (or processing) takes place (or occurs) for a secondtime. For example, with an esterification, some of the free fatty acidsand methanol is converted to biodiesel and water in a 2^(nd) stageesterification reactor.

As used herein, “third stage reactor” refers to a reactor or vessel inwhich a reaction (or processing) takes place (or occurs) for a thirdtime. For example, with an esterification, some of the free fatty acidsand methanol is converted to biodiesel and water in a 3^(rd) stageesterification reactor.

As used herein, “triglycerides” refers to an ester formed from amolecule of glycerol and three molecules of fatty acids. The structureof a triglyceride is shown below.

As used herein, “crude reaction product” refers to the product of areaction that is initially obtained, prior to a purification step.

As used herein, “immobilized on a solid support” refers to any techniquein which reagents are bound (i.e., immobilized or insolubilized) on asupport, to prevent them from being removed during use.

As used herein, “continuous” refers to refers to an event that isuninterrupted in time; without cessation.

As used herein, “batch mode” refers to a manufacturing process in whichmaterials are fed into the manufacturing process in batches, and theproduct is produced in batches. It differs from “continuous mode” wherestarting materials are continuously fed into the manufacturing processand product is continuously produced.

As used herein, “repeat,” “repeated,” or “repeating” refers to doingsomething or performing an operation the same way, substantially thesame way, or in an equivalent manner as previously done.

As used herein, “glycerin” refers to propane-1,2,3-triol. It has thestructure shown below.

As used herein, “transesterifying” refers to the process of exchangingthe organic group R₁ of an ester with the organic group R₂ of an alcohol(shown below as the methyl group of methanol). Transesterification isthe main reaction for converting transglycerides in oil to biodiesel.The transesterification process includes the reaction of an alcohol(such as methanol) with the triglyceride oils contained in vegetableoils, animal fats, or recycled greases, forming fatty acid alkyl esters(biodiesel) and glycerin. The reaction typically requires heat and astrong base catalyst, such as sodium hydroxide or potassium hydroxide.With respect to biodiesel, a transesterification reaction is shownbelow.

As such, the transesterification is typically represented by:alcohol+ester→different alcohol+different ester.

As used herein, “Biocatalyst A solid catalyst” refers to amethanol-resistant enzyme biocatalyst developed by TransBiodiesel(Israel) that is capable of esterifying/transesterifying oil componentsand short-chain alcohols to form biodiesel.

As used herein, “enzyme biocatalyst” refers to an immobilized enzyme,typically used for the production of biodiesel. The “biocatalyst” ismultifunctional it converts a wide-range grade of vegetable oil andanimal fat to biodiesel with minimal waste products. The enzymes aretypically biodegradable and safe to human use. Enzymes are proteins thatincrease (biologically catalyze) the rates of chemical reactions andtherefore are called sometimes “biocatalysts.” Enzyme activity can beaffected by other molecules (inhibitors) such as methanol or ethanol.Inhibitors are molecules that decrease enzyme activity; while activatorssuch as Free Fatty Acid are molecules that increase activity. Theenzymes are immobilized in order to protect them from a direct contactwith the inhibitors. The enzymes are lipase derived.

As used herein, “degrade” refers to making something worse in quality orperformance; to lower the purity of a material, typically occurring whenthe desired comp[und is converted to an undesired compound.

As used herein, “sodium methylate” refers to sodium methoxide, achemical compound, with formula CH₃ONa.

As used herein, “optionally” refers to a step, process or method that iseither carried out, or is not carried out.

As used herein, “sterols” refers to a subgroup of steroids with ahydroxyl group at the 3-position of the A-ring. This hydroxyl group isoften esterified with a fatty acid (for example, cholesterol ester). Thehydrocarbon chain of the fatty-acid substituent varies in length,usually from 16 to 20 carbon atoms, and can be saturated or unsaturated.Sterols commonly contain one or more double bonds in the ring structureand also a variety of substituents attached to the rings. Sterols andtheir fatty-acid esters are essentially water insoluble. They occurnaturally in plants, animals, and fungi, with the most familiar type ofanimal sterol being cholesterol.

As used herein, “monoglycerides” (more correctly known asmonoacylglycerols) refers to a glyceride consisting of one fatty acidchain covalently bonded to a glycerol molecule through an ester linkage.Monoacylglycerides can be broadly divided into two groups;1-monoacylglycerides and 2-monoacylglycerides, depending on the positionof the ester bond on the glycerol moiety.

As used herein, “diglycerides” refers to a glyceride consisting of twofatty acid chains covalently bonded to a glycerol molecule through esterlinkages.

As used herein, “triglycerides” refers to a glyceride consisting ofthree fatty acid chains covalently bonded to a glycerol molecule throughester linkages.

As used herein, “convert,” “converted,” or “converting” refers tochanging (something) into another form, substance, state, or product; totransform. For example, the biocatalyst converts a wide-range grade ofvegetable oil and animal fat to biodiesel, with minimal waste products.

As used herein, “acid number” refers to the mass of potassium hydroxide(KOH) in milligrams that is required to neutralize one gram of chemicalsubstance. The acid number is a measure of the amount of carboxylic acidgroups in a chemical compound, such as a fatty acid.

As used herein, “flash point” refers to the lowest temperature at whicha volatile material can vaporize to form an ignitable mixture in air.

As used herein, “moisture content” refers to the quantity of watercontained in a material.

As used herein, “sulfur content” refers to the amount of sulfur in amaterial.

As used herein, “phosphorus content” refers to the amount of phosphorousin a material.

As used herein, “content of polymerized triglycerides” refers to theamount of polymerized triglycerides present in a sample of biodieselfeedstock. Polymerized triglycerides are formed, for example, from fryergrease during heating at high temperature for a period of time.

As used herein, “sterols content” refers to the quantity of sterols in amaterial, particularly in a plant, an, animal, or a fungus.

As used herein, “activated carbon” also called activated charcoal,activated coal, or carbo activatus, refers to a form of carbon processedto be riddled with small, low-volume pores that increase the surfacearea available for adsorption or chemical reactions.

As used herein, “pure” refers to a material that is not mixed with anyappreciable or significant amount of other materials, e.g., that is notcontaminated in any substantial way. For example, a pure substance canhave a purity of at least 99 wt. %, at least 99.5 wt. %, or at least99.9 wt. %.

In specific embodiments, steps of a process that are carried out areindicated by a solid-lined arrow (see, FIGS. 1-6). Alternatively, inspecific embodiments, steps of a process that are optionally carried outare indicated by a dashed-lined arrow (see, FIGS. 1-6). It isappreciated that those of skill in the art of biodiesel productionunderstand and appreciate that for convenience and brevity purposes,such optional steps may be described as affirmatively being carried out,but that such steps, however, are optional and as such, are notnecessarily carried out.

Pretreatment of Biodiesel Feedstock

The pretreatment process is employed to ensure as reasonably feasiblethe quality, yield, and downstream operational efficiency in thebiodiesel refining process. This process removes or separates solidparticles, sulfur, phosphorus, phosphatides, gums, sterols, metalsand/or other color bodies from the feedstock.

Pretreatment of fats, oils and grease-based feedstocks can be carriedout with a continuous distillation process. In a continuous process,time that the feedstock remains in the column is relatively short, andhence the degree of polymerization is reduced.

The maximum permissible temperature is typically dependent upon how muchthe oils polymerize under the specific conditions. Under thepretreatment process, pre-filtered, dried and homogenized feed oilenters a heat exchanger (re boiler) using hot oil as thermic fluid,where it is heated to process temp of about 200-230° C. Feed then getsflashed from the re-boiler and enters the column from the bottom andflows upward, which operates under vacuum of about 27 inches of Hg. Thecolumn containing structured packing. The high volatile components inthe vapor state flow upwards to the top of the column. Less volatilecomponents (e.g., color bodies, metals, sterols, sulfur, gums etc.)remain in the bottom of the column.

The overhead vapors, which include mainly triglycerides and free fattyacids, are recycled with a reflux ratio of 1-1.5 to further maximize thepurity to about 99.95 wt. %. After the desired purity is achieved, thevapors are condensed using chiller. The clean oil is further sent to aholding tank, which is now ready for the transesterification and/or theesterification. The bottoms include polymerized oil that containssulfur, phosphorus, chlorophyll, phosphatides, gums, sterols and metalslike calcium, magnesium, iron, copper, sodium and potassium.

Referring to FIG. 4, a process flow diagram is provided for thepretreatment of biodiesel feedstock (401). Briefly stated, if abiodiesel feedstock (403) includes solid particles greater than 2microns (405), the biodiesel feedstock (403) is filtered (407), toremove or separate the solid particles greater than 2 microns. Thefiltering (407) of biodiesel feedstock (403) is carried out (e.g.,repeated) until the biodiesel feedstock (403) does not include asignificant or appreciable amount of solid particles greater than 2microns (405). The biodiesel feedstock (403) that does not include asignificant or appreciable amount of solid particles greater than 2microns (405) is distilled (409). The distillation (409) is carried outto provide a distillate and residue (411). The distillate (411) isdistilled (409) to provide a subsequent distillate (411) and subsequentresidue (411). The distillation is carried out (e.g., repeated) until nosignificant or appreciable amount of residue (411) is obtained. Once nosignificant or appreciable amount of residue (411) is obtained from theone or more distillations (409), the one or more distillates (411) arecombined and stored (not shown), to provide a purified biodieselfeedstock (413).

Referring to FIG. 1, a process flow diagram is provided for thepretreatment of biodiesel feedstock (101). Briefly stated, a biodieselfeedstock (103) is filtered (117) to provide a filtrate (105) andretentate (107). The filtering (117) can be repeated (127) one or moretimes. The retentate (107) is non-toxic, and can safely be disposed,e.g., in a land fill. Water and/or moisture are removed or separated(119) from the filtrate (105), to provide a dried filtrate (109). Thedried filtrate (109) is distilled (121), to provide a distillate (111)and residue (113). The distillate (111) and residue (113) can beseparated. The distillate (111) itself is distilled (121), i.e., theprocess is repeated (123), such that the distilling (121), to providedistillate (111) and residue (113), is carried out, wherein thedistillate (111) itself is subsequently distilled (121). The distilling(121) of the distillate (111) can be repeated (123) one or more times,to provide a subsequent distillate (111) and subsequent residue (113).The process is repeated (123), one or more times. Each of the residues(113) is non-toxic and can safely be disposed, e.g., in a land fill.Finally, the distillate (111) is stored (125), to provide a purifiedbiodiesel feedstock (115).

Each step of the pretreatment of biodiesel feedstock (101) canindependently be carried out in a continuous fashion, or in a batchmode.

Biodiesel Feedstock

The pretreatment (and any subsequent processes) can be carried outemploying a wide-range of biodiesel feedstocks (103). For example, thebiodiesel feedstocks (103) can include at least one of fats, oils, andgrease.

Specifically, the biodiesel feedstocks (103) can include at least one ofedible oils, inedible oils, fats, greases, oils produced frommicrobial/biological/biotechnology/fermentation/metabolic activity, orsimilar-based process, brown grease, trap grease, used cooking oil, usedcooking fat, animal fat, animal grease, and fatty acid distillate.

Specifically, the biodiesel feedstocks (103) can include at least one oftallow, pork fat, poultry fat, lard, choice white grease, algae oil,crude vegetable oils, soybean oil, corn oil, coffee oil, hemp oil,linseed oil, rice bran oil, jojoba oil, tall oil, mustard oil,distillers grain oil (DDG corn oil), Jatropha oil, camellia oil,rapeseed oil, canola oil, moring a oil, pongamia oil, sunflower oil,safflower oil, crude palm oil, palm kernel oil, palm fatty aciddistillate, palm sludge oil, coconut oil, and their derivatives(including genetically modified and otherwise).

The biodiesel feedstocks (103) will typically include a significant andappreciable amount of free fatty acids. In specific embodiments, thebiodiesel feedstocks (103) includes up to about 100 wt. % free fattyacids. In specific embodiments, the biodiesel feedstocks (103) includesabout 0.2 wt. % to about 100 wt. % free fatty acids. In specificembodiments, the biodiesel feedstocks (103) includes about 1 wt. % toabout 99 wt. % free fatty acids. In specific embodiments, the biodieselfeedstocks (103) includes about 5 wt. % to about 99 wt. % free fattyacids.

Filtering

The biodiesel feedstock (103) is filtered (117), to provide a filtrate(105) and retentate (107). The filtrate (105) will typically passthrough the filter, as the retentate (107) is retained by the filter.The filtering (117) can be repeated (127) one or more times. As such,the biodiesel feedstock (103) can be filtered (117) one or more times,to provide a filtrate (105) and one or more retentates (107). Inspecific embodiments, the repeating (127) is carried out until there islittle or no appreciable and significant amount of retentate (107). Whenthe biodiesel feedstock (103) is filtered (117) multiple times, theporosity or mesh size will typically vary from filter to filter. Forexample, the initial filtering (117) can be carried out with a filterhaving relatively larger openings (i.e., a lower Tyler mesh size, whichis the number of openings per linear inch of mesh). With each subsequentfiltering (117), a filter can be employed having relatively smalleropenings (i.e., a higher Tyler mesh size). The filtering (117) can becarried out such that relatively larger-sized solid particles areremoved or separated in the initial filtering (117). With eachsubsequent filtering (117), progressively smaller-sized solid particlesare removed or separated.

When the biodiesel feedstock (103) is filtered (117) multiple times asdescribed herein, smaller-sized solid particles can effectively andefficiently be removed or separated from the biodiesel feedstock (103),on an industrial or commercial scale. Additionally, smaller-sized solidparticles can effectively and efficiently be removed or separated fromthe biodiesel feedstock (103) with a decreased likelihood thatlarger-sized solid particles will interfere with (e.g., clog or gum-up)the filter having relatively smaller openings (i.e., a higher Tyler meshsize). In specific embodiments, the final filtering (117) is carried outemploying a filter having a requisite mesh size, such that solidparticles having a diameter up to 2 microns are effectively removed orseparated.

Specifically, the one or more filterings (117) can be carried out, suchthat at least about 50 wt. % of the solid particles having a diameter upto 2 microns are effectively removed or separated. More specifically,the one or more filterings (117) can be carried out, such that at leastabout 75 wt. % of the solid particles having a diameter up to 2 micronsare effectively removed or separated. More specifically, the one or morefilterings (117) can be carried out, such that at least about 85 wt. %of the solid particles having a diameter up to 2 microns are effectivelyremoved or separated. More specifically, the one or more filterings(117) can be carried out, such that at least about 90 wt. % of the solidparticles having a diameter up to 2 microns are effectively removed orseparated. More specifically, the one or more filterings (117) can becarried out, such that up to about 100 wt. % of the solid particleshaving a diameter up to 2 microns are effectively removed or separated.

The biodiesel feedstock (103) can be filtered (117) one time, ormultiple times. For example, the biodiesel feedstock (103) can befiltered (117) about 1-25 times, about 1-15 times, about 1-10 times, orabout 1-5 times. Specifically, the biodiesel feedstock (103) can befiltered (117) at least about 2 times, at least about 3 times, at leastabout 4 times, or at least about 5 times.

In specific embodiments, the filtering (117) is carried out in a batchmode. Alternatively, in specific embodiments, the filtering (117) iscarried out in a continuous fashion. In specific embodiments, thefiltering (117) is continuous, and can include a single filter. Inalternative specific embodiments, the filtering (117) is continuous, andcan include multiple filters, as described herein.

The filtering (117) of the biodiesel feedstock (101) can be carried outon a commercial or industrial scale. For example, at least about 100gallons of biodiesel feedstock (101) can be filtered (117).Specifically, within about 24 hours, at least about 100 gallons ofbiodiesel feedstock (101) can be filtered (117). Additionally, at leastabout 1,000 gallons of biodiesel feedstock (101) can be filtered (117).Specifically, within about 24 hours, at least about 1,000 gallons ofbiodiesel feedstock (101) can be filtered (117).

Removing Moisture and/or Water

Water and/or moisture can be removed or separated (119) from thefiltrate (105), to provide a dried filtrate (109). The moisture can beremoved by employing distillation and/or evaporators, in single ormulti-stages, with or without vacuum. Moisture and/or water can bepresent in the feedstock from about 0.1 wt. % to about 99.5 wt. %, withfinal oil stream having about 1 wt. % or less moisture in it, typicallyabout 500-2000 ppm. As such, in specific embodiments of the invention,the removing moisture and/or water can occur (e.g., can be carried out)during the one or more distillings (121).

Distilling

The dried filtrate (109) is distilled (121), to provide a distillate(111) and residue (113). The dried filtrate (109) is distilled (121)under suitable conditions, effective to provide the distillate (111) andresidue (113). For example, the distilling (121) can be carried out atelevated temperatures and/or reduced pressures (e.g., under vacuum).Specifically, the distilling (121) can be carried out at elevatedtemperatures, e.g., at about 100° C. to about 530° C. Specifically, thedistilling (121) can be carried out at reduced pressures, e.g., about 24to about 29.92 inches of mercury (Hg).

The distilling (121) can be repeated (123) one or more times. As such,the dried filtrate (109) can be distilled (121), to provide distillate(111) and residue (113), wherein the distillate (111) is distilled (121)providing yet a subsequent distillate (111), and optionally a subsequentresidue (113). In specific embodiments, the repeating (123) is carriedout until there is little or no appreciable and significant amount ofresidue (113). In more specific embodiments, the repeating (123) iscarried out until less than about 5 wt. % residue (113) is obtained,relative to the biodiesel feedstock (101). In more specific embodiments,the repeating (123) is carried out until less than about 1 wt. % residue(113) is obtained, relative to the biodiesel feedstock (101). In morespecific embodiments, the repeating (123) is carried out until less thanabout 0.5 wt. % residue (113) is obtained, relative to the biodieselfeedstock (101).

The dried filtrate (109) and/or distillate (111) can be distilled (121)one time, or multiple times. For example, the dried filtrate (109)and/or distillate (111) can be distilled (121) about 1-25 times, about1-15 times, about 1-10 times, or about 1-5 times. Specifically, thedried filtrate (109) and/or distillate (111) can be distilled (121) atleast about 2 times, at least about 3 times, at least about 4 times, orat least about 5 times.

In specific embodiments, the dried filtrate (109) and/or distillate(111) are distilled (121) multiple times, such that the residue (113) isabout 0.1% to about 10% the weight of the dried filtrate (109) and/ordistillate (111). In further specific embodiments, the dried filtrate(109) and/or distillate (111) are distilled (121) multiple times, suchthat the residue (113) is about 0.2% to about 6% the weight of the driedfiltrate (109) and/or distillate (111).

In specific embodiments, the distilling (121) is carried out in a batchmode. Alternatively, in specific embodiments, the distilling (121) iscarried out in a continuous fashion. In specific embodiments, thedistilling (121) is continuous, and can include a single stagedistillation column. In alternative specific embodiments, the distilling(121) is continuous, and can include a multi-stage distillation column.Additionally, the single stage (or multi stage) distillation column canoperate with or without vacuum.

The distilling (121) can be carried out on a commercial or industrialscale. For example, the distilling (121) can be carried out to provideat least about 100 gallons of distillate (111). Specifically, thedistilling (121) can be carried out to provide, within about 24 hours,at least about 100 gallons of distillate (111). Additionally, thedistilling (121) can be carried out to provide at least about 1,000gallons of distillate (111). Specifically, the distilling (121) can becarried out to provide, within about 24 hours, at least about 1,000gallons of distillate (111).

The one or more distillings (121) are carried out to increase the puritylevel of the distillate (111). This can be accomplished, e.g., byremoving, separating, or lowering the amount of the one or moreimpurities located therein. When impurities are removed or separated viadistillation (121), the residue (113) will be enriched in thoseimpurities, relative to the distillate (111).

In specific embodiments, the one or more distillings (121) are carriedout to provide distillate (111) and residue (113), such that relative tothe distillate (111), the residue (113) is enriched in at least one ofsulfur, phosphorus, gums/lipids, sterols, calcium, magnesium, iron,copper, cobalt, manganese, nickel, sodium, potassium, chlorophyll,carotenoids, xanthophylls, proteins and carbohydrates, aldehydes,ketones, carboxylic acids, perchloroethylene, polyaromatic hydrocarbons,polychlorinated hydrocarbons, polymerized triglycerides, pesticides,soaps, detergents, sulfonates, sulfates, phosphatides, phytosterols,sitosterols, cholesterol, sterol glucosides, oils and fats, other traceimpurities, and other colored bodies.

In specific embodiments, the one or more distillings (121) are carriedout to provide distillate (111) and residue (113), such that relative tothe residue (113), the distillate (111) is enriched in at least one oftriglycerides and free fatty acids.

The distillate (111) will typically include an appreciable andsignificant amount of at least one of triglycerides and free fattyacids. In specific embodiments, the distillate (111) includes up toabout 95 wt. % of at least one of triglycerides and free fatty acids. Infurther specific embodiments, the distillate (111) includes up to about99 wt. % of at least one of triglycerides and free fatty acids. Infurther specific embodiments, the distillate (111) includes up to about99.5 wt. % of at least one of triglycerides and free fatty acids. Infurther specific embodiments, the distillate (111) includes up to about99.995 wt. % of at least one of triglycerides and free fatty acids.

In specific embodiments, the distillate (111) includes at least one oftriglycerides and free fatty acids, wherein the at least one oftriglycerides and free fatty acids combined include less than about 7ppm phosphorus, less than about 7 ppm sulfur, and less than about 10 ppmof all other metals combined. In further specific embodiments, thedistillate (111) includes at least one of triglycerides and free fattyacids, wherein the at least one of triglycerides and free fatty acidscombined include less than about 7 ppm sulfur.

Storing

The distillate (111) is stored (125), to provide a purified biodieselfeedstock (115). The distillate (111) can be stored (125), e.g., in asuitable manner, in a suitable vessel, under suitable conditions, andfor a suitable period of time, to provide a purified biodiesel feedstock(115).

Specifically, the distillate (111) can be stored (125) at about ambienttemperature and pressure. Alternatively, the distillate (111) can bestored (125) below room temperature. Alternatively, the distillate (111)can be stored (125) at a temperature of about 0° C. to about 60° C., ata temperature of about 5° C. to about 50° C., at a temperature of about10° C. to about 40° C., or at a temperature of about 10° C. to about 30°C.

The distillate (111) can be stored (125) for a suitable period of time.For example, the distillate (111) can be stored (125) for up to about 6months, up to about 1 month, up to about 1 week, or up to about 24hours. Specifically, the distillate (111) can be stored (125) for about1 minute to about 48 hours, about 10 minutes to about 48 hours, or about1 hour to about 24 hours.

Impurities Present in Biodiesel Feedstock

The pretreatment of biodiesel feedstock (101) can be carried out toincrease the purity level of the biodiesel feedstock (101). As such, inspecific embodiments, the pretreatment of biodiesel feedstock (101) is amethod of purifying a biodiesel feedstock (101). This method ofpurification can be accomplished, e.g., by removing, separating, orlowering the amount of the one or more impurities located therein.Suitable impurities typically present in biodiesel feedstock (101)include, e.g., those illustrated in Table A herein, in the amountsillustrated therein.

In specific embodiments, the biodiesel feedstock (101), prior to thepretreatment process, is analyzed to determine the qualitative nature ofimpurities located therein. In specific embodiments, the biodieselfeedstock (101), prior to the pretreatment process, is analyzed todetermine the quantitative nature of impurities located therein.

In specific embodiments, the biodiesel feedstock (101) includes at leastone of triglycerides, gums, soaps, detergents, unsaponifiables,phosphatides, metals, phosphorus, sulfur, sulfates, sulfonates,sulfides, polyaromatic hydrocarbons, polychlorinated hydrocarbons,polyethylene, plant based sterols, animal based sterols, moisture, andwater.

In specific embodiments, the biodiesel feedstock (101) includes elevatedlevels of at least one of water, sulfur, phosphorus, gums/lipids,sterols, calcium, magnesium, iron, copper, cobalt, manganese, nickel,sodium, potassium, chlorophyll, carotenoids, xanthophylls, proteins andcarbohydrates, aldehydes, ketones, carboxylic acids, perchloroethylene,polyaromatic hydrocarbons, polychlorinated hydrocarbons, polymerizedtriglycerides, pesticides, soaps, detergents, sulfonates, sulfates,phosphatides, phytosterols, sitosterols, cholesterol, sterol glucosides,and other colored bodies.

In specific embodiments, the biodiesel feedstock (101) includes up toabout 20,000 ppm of at least one of sulfur, sulfates, sulfides, andsulfonates.

In specific embodiments, the biodiesel feedstock (101) includes up toabout 4000 ppmw phosphorus.

In specific embodiments, the pretreatment of biodiesel feedstock (101)is carried out to remove or separate from the feedstock (101) at leastone of water, sulfur, phosphorus, gums, strerols, calcium, magnesium,iron, copper, sodium, potassium, chlorophyll, phosphatides, and coloredbodies.

In specific embodiments, the pretreatment of biodiesel feedstock (101)is carried out to remove or separate at least one of water, sulfur,phosphorus, gums/lipids, sterols, calcium, magnesium, iron, copper,cobalt, manganese, nickel, sodium, potassium, chlorophyll, carotenoids,xanthophylls, proteins and carbohydrates, aldehydes, ketones, carboxylicacids, perchloroethylene, polyaromatic hydrocarbons, polychlorinatedhydrocarbons, polymerized triglycerides, pesticides, soaps, detergents,sulfonates, sulfates, phosphatides, phytosterols, sitosterols,cholesterol, sterol glucosides, oils and fats, other trace impurities,and other colored bodies.

Esterification of Free Fatty Acids

As described herein, an esterification is the general name for achemical reaction in which two reactants (typically an alcohol and anacid) form a carboxylic ester as the desired reaction product, and wateras the side-product. With reference to Biodiesel, free fatty acids(present in the feedstock) react with the reagent methanol in presenceof catalyst (optionally at an elevated temperature and/or pressure) toform biodiesel and water.

Employing an ion exchange resin and a solid, heterogeneousesterification catalyst, the esterification process described herein canprocess feedstock containing up to 100% FFAs (multi-feedstocks), in 3stages, with an 99.8 wt. % or higher conversion. The esterificationcatalyst can last about 6-9 months, and not only lowers the feedstockcosts but also improves the biodiesel and glycerin quality significantlywithout the use of toxic acids and chemicals. Because of theheterogeneous catalyst, no soap is produced in this process andbiodiesel-glycerin separation (in absence of soaps and salts) becomesrelatively easier.

The esterification described can effectively convert any feedstock, evenat very high FFA content. Other catalysts typically suffer fromincomplete conversion, resulting in yield loss and saponification in thedownstream transesterification unit. The fast kinetics of the solidheterogeneous esterification catalyst described herein allow for rapidthroughput, whereas other esterification processes may limit productionby creating a bottleneck in the process.

The dried and clean feedstock from the pretreatment unit passes througha guard bed with ion exchange resin, which filters any trace elements orcomponents like gums/metals that can poison the solid heterogeneousesterification catalyst. It consists of a straight flow through 2 stageguard bed column in series (lead-lag) with no application of heat orpressure.

The feedstock is premixed with methanol using a shear mixer and thenheated to operating parameters of about 185° F. and about 30 psi. Beingan equilibrium reaction, molar flow rate of methanol is about 100% inexcess of the stoichiometric requirements, with respect to the freefatty acid content of the feedstock entering into the 1^(st) stagereactor. The feedstock enters the reactor from the top and uniformlyflows downward with the aid of a distributor. The reactor is a packedbed column with the solid heterogeneous esterification catalyst thatincludes screens at the top and bottom to hold the catalyst in a givenarea based on the optimization parameters like L/D ratio, Diameter ofthe column, etc. Residence time (about 30-45 minutes) combined withtemperature, pressure, molar flow rates, fluid dynamics and columndesign helps achieve excellent conversion (about 90% approx.), yieldsand operating efficiencies.

To maximize the conversion of free fatty acids into biodiesel, waterwhich acts as a rate limiting agent, is removed or separated between thereactor stages to drive the reaction to completion. Upon conversion, the1^(st) stage reactor bottoms are sent to a flash still (operating undervacuum of about 26 inches Hg, with a temperature of about 195° F.),where excess water and methanol are removed or separated.

The water-methanol stream from overheads of this and subsequent flashstills are sent to methanol distillation column (atmospheric pressure,146° F.), where the methanol is purified to about 99.80% purity. Bottomsof the flash still which include biodiesel, triglycerides andunconverted FFAs, are sent to 2^(nd) stage reactor where relatively puremethanol is mixed (100% molar excess, with respect to the FFA content)and the whole stream is heated to process temperature of about 185° F.and introduced into the 2^(nd) stage reactor.

The output of the 2^(nd) stage reactor is typically a stream containingless than 1% FFA with a mix of biodiesel and triglycerides, along withexcess methanol and water formed from the reaction. The stream is sentto 2^(nd) stage flash still where methanol and water is flashed off.

Bottoms of the 2^(nd) stage flash still, which include triglycerides,biodiesel and less than 1 wt. % FFA are sent to a final 3^(rd) stagereactor, which operates similarly to the first and second stage reactorswith respect to flow rates, temp, pressure and design of the column. Theresulting triglyceride and biodiesel stream from the 3^(rd) stagereactor has moisture and methanol content less than about 0.2% whichproceeds to the transesterification process.

Water/methanol flashed from the flash stills is sent to methanoldistillation column, which purifies methanol to about 99.70 wt. %purity. The purified and recovered methanol is used (recycled) in theesterification process (or transesterification process).

Referring to FIG. 5, a process flow diagram is provided for theesterification of free fatty acids (503), present in biodieselfeedstock. Briefly stated, the biodiesel feedstock (503) is pretreatedwith an ion exchange resin, to provide a treated biodiesel feedstock(507). The free fatty acids present in the treated biodiesel feedstock(507) are then esterified. Specifically, the treated biodiesel feedstock(507) is contacted (509) with an esterifying reagent and catalyst, toprovide an esterification mixture (511). The esterification mixture(511) includes the treated biodiesel feedstock (507), which in turnincludes the free fatty acids. The esterification mixture (511) alsoincludes methanol (as the esterifying reagent) and a solid,heterogeneous esterification catalyst. The esterification mixture (511)is subject to esterification conditions (515), such that the free fattyacids present therein are esterified, to provide an esterificationreaction product (517) that includes biodiesel as the desired productand water as a by-product. When a stoichiometric excess (e.g., 1.25molar equivalent) of methanol is employed in the esterification (e.g.,509 and 511), the esterification reaction product (517) will alsotypically include unreacted methanol (517). The esterification reactionproduct (517) is separated, to provide biodiesel (523), and a mixture(521) of methanol and water.

If the biodiesel (523) contains a significant and appreciable amount ofunreacted free fatty acids (533), the biodiesel (523) is contacted (509)with an esterifying reagent and catalyst, to provide a subsequentesterification mixture (511). The subsequent esterification mixture(511) is subject to esterification conditions (515), such that the freefatty acids present therein are esterified, to provide a subsequentesterification reaction product (517) that includes biodiesel as thedesired product and water as a by-product. Again, when a stoichiometricexcess of methanol is employed in the subsequent esterification (e.g.,509 and 511), the subsequent esterification reaction product (517) willalso typically include unreacted methanol (517). The subsequentesterification reaction product (517) is separated, to provide asubsequent biodiesel (523), and a subsequent mixture (521) of methanoland water.

The esterification is carried out (e.g., repeated) until no significantor appreciable amount of free fatty acids (533) is obtained. Once nosignificant or appreciable amount of free fatty acids (533) is obtainedin the biodiesel (523) is used as biodiesel feedstock (539).

The mixture (521) of methanol and water is separated (527) to providemethanol (529) and water (531). The methanol (529) is purified viadistillation (535) to provide purified methanol (537). The purifiedmethanol (537) can be reused (513) in a subsequent esterificationreaction and/or transesterification reaction.

Referring to FIG. 2, a process flow diagram is provided for theesterification of free fatty acids (201), present in biodieselfeedstock. The biodiesel feedstock (203) can include purified biodieselfeedstock (115) obtained in the pretreatment of biodiesel feedstock (notshown, see FIG. 1). Briefly stated, a biodiesel feedstock (203) ispretreated (202) with guard bed column reactors (that includes an ionexchange resin, such as, e.g., Ambersep™ BD19 purification resin), toprovide a treated biodiesel feedstock (205). The treated biodieselfeedstock (205) is contacted with an esterifying reagent and catalyst(204), such as methanol and a solid heterogeneous catalyst. The mixture(207) of biodiesel feedstock, methanol, and solid heterogeneous catalystis subject to esterification conditions (220), to provide a reactionproduct (215) that includes biodiesel, water, methanol, andtriglycerides. The reaction product (215) is separated (212), to providebiodiesel (217), water (219), and methanol (221). The methanol (221) isdistilled off (214), to provide purified methanol (223). The purifiedmethanol (223) is reused (218) to form a mixture (207), which isesterified (220 or 206).

The mixture (207) is subject to esterification conditions (206), toprovide a reaction product (209). The reaction product (209) isseparated, to provide a mixture (211) and reaction product (213). Thereaction product (213) contacts (204) reagent and catalyst, to providemixture (217), which is subjected to esterifying conditions (206), toprovide reaction product (209). Reaction product (209) undergoes aseparation (208), to provide mixture (211) and reaction product (213).The process is repeated (216), one or more times, until the finalesterifying (220) provides reaction product (215).

Each step of the esterification of free fatty acids (201) canindependently be carried out in a continuous fashion, or in a batchmode.

Pretreating with Guard Bed Column Reactors

Biodiesel feedstock (203) is pretreated (202) with guard bed columnreactors, to provide a treated biodiesel feedstock (205). Thepretreatment (202) is carried out to remove or separate at least one oftrace elements, impurities and foulants selected from gums, metals,cations, proteins, and phospholipids. As such, relative to the treatedbiodiesel feedstock (205), the biodiesel feedstock (203) has elevatedlevels of at least one of trace elements, impurities and foulantsselected from gums, metals, cations, proteins, and phospholipids.

In specific embodiments, prior to the pretreating (202), the biodieselfeedstock (203) is premixed with methanol. In alternative specificembodiments, prior to the pretreating (202), the biodiesel feedstock(203) is not premixed with methanol.

In specific embodiments, the biodiesel feedstock (203) is pretreated(202) at standard temperature. In alternative specific embodiments, thebiodiesel feedstock (203) is pretreated (202) at an elevatedtemperature.

In specific embodiments, the biodiesel feedstock (203) is pretreated(202) at standard pressure. In alternative specific embodiments, thebiodiesel feedstock (203) is pretreated (202) at an elevated pressure.

In specific embodiments, the biodiesel feedstock (203) is pretreated(202) by passing through an Ambersep™ BD19 purification resin. In morespecific embodiments, the biodiesel feedstock (203) is pretreated (202)with an Ambersep™ BD19 purification resin, which consists of a straight,flow-through 2 stage guard bed column reactors in series.

Esterifying

Mixture (207) that includes biodiesel feedstock, methanol, and solidheterogeneous esterification catalyst is subject to esterification (220or 206) conditions. The biodiesel feedstock (203), the treated biodieselfeedstock (205), and the biodiesel feedstock present in mixture (207)each include free fatty acids. These free fatty acids present inbiodiesel feedstock are esterified with the methanol, with the aid ofthe solid heterogeneous catalyst.

Mixture (207) is subject to esterification (220 or 206) conditions, toprovide reaction product (215) that includes biodiesel, water, methanol,and triglycerides. Alternatively, mixture (207) is subject toesterification (220 or 206) conditions, to provide reaction product(209) that includes biodiesel, water, methanol, triglycerides, and freefatty acids. When mixture (207) is subject to esterification (220 or206) conditions, to provide reaction product (209), mixture (211) thatincludes methanol and water is separated (208) from the reaction product(209), to provide reaction product (213) that includes biodiesel,triglycerides, and free fatty acids. Reaction product (213) issubsequently contacted (204) with reagent and catalyst, to form mixture(207), which is subject to esterification conditions (206). This process(esterification (206) and separation (208)) is optionally repeated (216)one or more times, until the final esterifying (220) substantiallyprovides reaction product (215).

The esterifying (220 or 206) can be carried out under suitableesterification conditions. Typically, the esterification (220 or 206)can be carried out at an elevated temperature. In specific embodiments,the methanol, catalyst, and biodiesel feedstock are heated to atemperature of at least about 170° F. (76.67° C.). In further specificembodiments, the methanol, catalyst, and biodiesel feedstock are heatedto a temperature of up to about 200° F. (93.33° C.). In further specificembodiments, the methanol, catalyst, and biodiesel feedstock are heatedto a temperature of between about 170° F. (76.67° C.) to about 200° F.(93.33° C.).

The esterifying (220 or 206) can be carried out at an elevated pressure.In specific embodiments, the methanol, catalyst, and biodiesel feedstockare heated at a pressure of at least about 15 psi (1.02 atm). In furtherspecific embodiments, the methanol, catalyst, and biodiesel feedstockare heated at a pressure of up to about 50 psi (3.40 atm).

The esterifying (220 or 206) is carried out for a requisite period oftime. In specific embodiments, the methanol, catalyst, and biodieselfeedstock are heated for a period of time of at least about 15 minutes.In further specific embodiments, the methanol, catalyst, and biodieselfeedstock are heated for a period of time of up to about 75 minutes. Infurther specific embodiments, the methanol, catalyst, and biodieselfeedstock are heated for a period of time of about 15 minutes to about75 minutes.

When the esterifying (220 or 206) is carried out on a commercial orindustrial scale, the reagent can be employed in a molar orstoichiometric excess. This will assist in driving the reaction tocompletion. This is especially so when the esterifying (206) andseparating (208) are carried out one or more times, thereby removing orseparating water from each of the one or more reaction products. Withthe esterifying (220 or 206) described herein, the methanol can beemployed in a molar or stoichiometric excess, relative to the free fattyacid content of the biodiesel feedstock.

In specific embodiments, the methanol is employed in at least a 5 molaror stoichiometric excess, relative to the free fatty acid content of thebiodiesel feedstock. In further specific embodiments, the methanol isemployed in at least a 10 molar or stoichiometric excess, relative tothe free fatty acid content of the biodiesel feedstock. In furtherspecific embodiments, the methanol is employed in at least a 20 molar orstoichiometric excess, relative to the free fatty acid content of thebiodiesel feedstock. In further specific embodiments, the methanol isemployed in up to a 100 molar or stoichiometric excess, relative to thefree fatty acid content of the biodiesel feedstock.

The esterifying (220 or 206) provides a reaction product (215 or 209)that aside from water, includes relatively few by-products. For example,in specific embodiments, the esterifying (220 or 206) provides areaction product (215 or 209) that includes little or no (e.g., lessthan about 0.5 wt. %) soap product. In specific embodiments, theesterifying (220 or 206) provides a reaction product (215 or 209) thatincludes little or no (e.g., less than about 0.5 wt. %) salt product. Inspecific embodiments, the esterifying (220 or 206) provides a reactionproduct (215 or 209) that includes little or no (e.g., less than about0.5 wt. %) by-products.

The esterifying (220 or 206) employs methanol as the reagent, present inmixture (207). The methanol will have a requisite purity. For example,in specific embodiments, the methanol will have a purity of at leastabout 99 wt. %, at least about 99.5 wt. %, at least about 99.9 wt. %, orat least about 99.95 wt. %. In further specific embodiments, themethanol will have a purity of up to about 100 wt. %. Employing methanolhaving a requisite purity, within the esterifying (220 or 206), willassist in driving the esterification (220 or 206) to completion, whileproviding a relatively high yield and/or purity of desired product.

The esterifying (220 or 206) employs a solid heterogeneous catalyst,present in the mixture (207). In specific embodiments, the solidheterogeneous catalyst includes Amberlyst™ BD20 solid catalyst (Rohm andHaas). In specific embodiments, the solid heterogeneous catalyst isimmobilized on a solid support. In specific embodiments, the solidheterogeneous catalyst is non-toxic and is suitable for safely disposalin a land fill. It is believed that by employing a purified biodieselfeedstock (115) as the biodiesel feedstock (203), the commercial life ofthe solid heterogeneous catalyst will be extended. This can lower theactual cost of the solid heterogeneous catalyst, as well as the laborcosts and cost of down-time associated with replacing the solidheterogeneous catalyst.

In specific embodiments, the solid heterogeneous catalyst is active inthe esterification (220 or 206) for at least about 6 months. In furtherspecific embodiments, the solid heterogeneous catalyst is active in theesterification (220 or 206) for at least about 12 months. In furtherspecific embodiments, the solid heterogeneous catalyst is active in theesterification (220 or 206) for up to about 18 months.

The esterifying (206) can be repeated (216) one or more times. As such,the mixture (207) can be subjected to esterification (206) conditions,to provide reaction product (209), which can be separated into mixture(211) and reaction product (213). Reaction product (213) cansubsequently be contacted (204) with reagent and catalyst, to formmixture (207), which can be subjected to esterification (206)conditions.

The esterifying (220) is carried out one time. Additionally, theesterifying (206) is carried out zero or more times. When carried outtwo or more times, the esterifying (206) is repeated (216) zero or moretimes and the esterifying (220) is carried out one time. In specificembodiments, the esterifying (206) is carried out about 0-25 times,about 1-15 times, about 1-10 times, or about 1-5 times. In more specificembodiments, the esterifying (206) is carried out at least about 1 time,at least about 2 times, or at least about 3 times.

In specific embodiments, the repeating (216) is carried out until thefinal esterifying (220) substantially provides reaction product (215).In more specific embodiments, the repeating (216) is carried out untilthe final esterifying (220) substantially provides reaction product(215), that includes little or no (e.g., less than about 5 wt. %) freefatty acids. In further specific embodiments, the repeating (216) iscarried out until the final esterifying (220) provides reaction product(215), that includes less than about 1 wt. % free fatty acids. Infurther specific embodiments, the repeating (216) is carried out untilthe final esterifying (220) provides reaction product (215), thatincludes less than about 0.5 wt. % free fatty acids. In further specificembodiments, the repeating (216) is carried out until the finalesterifying (220) provides reaction product (215), that includes lessthan about 0.1 wt. % free fatty acids.

In specific embodiments, the esterifying (220 or 206) is carried out ina batch mode. Alternatively, in specific embodiments, the esterifying(220 or 206) is carried out in a continuous fashion.

In specific embodiments, the esterifying (220 or 206) is continuous, andcan include a single stage reactor. In alternative specific embodiments,the esterifying (220 or 206) is continuous, and can include amulti-stage reactor (e.g., first stage reactor, second stage reactor andthird stage reactor). A multi-stage reactor is a reference toesterifying (220) and one or more esterifyings (206), in FIG. 2.

When a multi-stage reactor is employed, each stage independentlyprovides for the conversion of free fatty acids and methanol tobiodiesel and water. In specific embodiments, each stage provides aconversion of at least about 80 wt. % of free fatty acids presenttherein, to biodiesel and water. In more specific embodiments, eachstage provides a conversion of at least about 90 wt. % of free fattyacids present therein, to biodiesel and water. In further specificembodiments, each stage provides a conversion of at least about 95 wt. %of free fatty acids present therein, to biodiesel and water.Additionally, the single stage (or multi stage) reactor can beconfigured to operate at elevated temperature and/or at elevatedpressure.

The esterifying (220 or 206) can independently be carried out on acommercial or industrial scale. For example, the esterifying (220 and206) can be carried out to provide at least about 100 gallons ofcombined reaction product (209 and 215). Specifically, the esterifying(220 and 206) can be carried out to provide, within about 24 hours, atleast about 100 gallons of combined reaction product (209 and 215).Additionally, the esterifying (220 and 206) can be carried out toprovide at least about 1,000 gallons of combined reaction product (209and 215). Specifically, the esterifying (220 and 206) can be carried outto provide, within about 24 hours, at least about 1,000 gallons ofcombined reaction product (209 and 215).

When the esterifying (220 or 206) is carried out as described herein,the free fatty acids are esterified with methanol, with a relativelyhigh conversion. In specific embodiments, the free fatty acids areesterified with methanol, with a combined conversion of at least about70 wt. %. In further specific embodiments, the free fatty acids areesterified with methanol, with a combined conversion of at least about85 wt. %. In further specific embodiments, the free fatty acids areesterified with methanol, with a combined conversion of at least about95 wt. %. In further specific embodiments, the free fatty acids areesterified with methanol, with a combined conversion of at least about98 wt. %. In further specific embodiments, the free fatty acids areesterified with methanol, with a combined conversion of at least about99 wt. %. In further specific embodiments, the free fatty acids areesterified with methanol, with a combined conversion of up to about 100wt. %.

Separating/Distilling

Each of the reaction product (209), mixture (211), and reaction product(215) can be separated (208, 210, and 212, respectively). For example,the reaction product (209) can be separated (208) to provide a mixture(211) of methanol and water, and reaction product (213) that includesbiodiesel, triglycerides, and free fatty acids. The mixture (211) can beseparated (210) to provide water (219) and methanol (221). The reactionproduct (215) can be separated (210) to provide biodiesel (217) thatincludes biodiesel and triglycerides, along with water (219), andmethanol (221). Each of the separations can independently be carriedout, e.g., by employing distillation. Additionally, the methanol (221)can be distilled (214) to provide purified methanol (223).

Each of the distillations in the esterification of free fatty acids(201) can independently be carried out under suitable conditions. Forexample, each of the distillations in the esterification of free fattyacids (201) can independently be carried out at elevated temperaturesand/or reduced pressures (e.g., under vacuum). Specifically, each of thedistillations in the esterification of free fatty acids (201) canindependently be carried out at elevated temperatures, e.g., at about80° C. to about 130° C. Specifically, each of the distillations in theesterification of free fatty acids (201) can independently be carriedout at reduced pressures, e.g., about 20 to about 29.92 inches ofmercury (Hg).

Each of the distillations in the esterification of free fatty acids(201) can independently be carried out one or more times. Each of thedistillations in the esterification of free fatty acids (201) canindependently be carried out about 1-5 times, about 1-4 times, about 1-3times, or about 1-2 times.

In specific embodiments, each of the distillations in the esterificationof free fatty acids (201) is independently carried out in a batch mode.Alternatively, in specific embodiments, each of the distillations in theesterification of free fatty acids (201) is independently carried out ina continuous fashion. In specific embodiments, any one or more of thedistillations in the esterification of free fatty acids (201) isindependently continuous, and includes a single stage distillationcolumn. In alternative specific embodiments, any one or more of thedistillations in the esterification of free fatty acids (201) isindependently continuous, and includes a multi-stage distillationcolumn. Additionally, each of the single stage (or multi stage)distillation column can independently operate with or without vacuum.

Each of the distillations in the esterification of free fatty acids(201) can independently be carried out on a commercial or industrialscale. For example, any one or more of the distillations in theesterification of free fatty acids (201) can independently be carriedout to provide at least about 100 gallons of distillate. Specifically,any one or more of the distillations in the esterification of free fattyacids (201) can independently be carried out to provide, within about 24hours, at least about 100 gallons of distillate. Additionally, any oneor more of the distillations in the esterification of free fatty acids(201) can independently be carried out to provide at least about 1,000gallons of distillate. Specifically, any one or more of thedistillations in the esterification of free fatty acids (201) canindependently be carried out to provide, within about 24 hours, at leastabout 1,000 gallons of distillate.

Reuse of Methanol

The esterification of free fatty acids (201) is carried out withmethanol as the reagent. For example, reagent (i.e., methanol) andcatalyst are added to the treated biodiesel feedstock (205), to formmixture (207) that includes biodiesel feedstock, methanol, and solidheterogeneous catalyst. As described herein, mixture (207) is subject toesterification (220 or 206) conditions, sufficient to esterify freefatty acids present in the mixture (207). Upon esterification (220 or206) of free fatty acids present in the mixture (207), reaction product(215 or 209, respectively) is obtained. Because a molar orstoichiometric excess of methanol is typically employed in theesterification (220 or 206), each of reaction products (215 and 209)will typically include methanol. This methanol can be recaptured,purified, and reused for a subsequent esterification (220 or 206), ortransesterification (see, FIG. 3).

Specifically, methanol present in reaction product (215) can beseparated (212), to provide, e.g., methanol (221), which can bedistilled (214) to provide purified methanol (223), which can be reused(218). Likewise, methanol present in reaction product (209) can beseparated (208), to provide, e.g., a mixture (211) that includesmethanol and water. Mixture (211) can be separated (210), to provide,e.g., methanol (221), which can be distilled (214) to provide purifiedmethanol (223), which can be reused (218).

When a molar or stoichiometric excess of methanol is employed in theesterification (220 or 206), each of reaction products (215 and 209)will typically include methanol. This excess methanol can be recaptured,purified, and reused for a subsequent esterification (220 or 206), ortransesterification (see, FIG. 3). In specific embodiments, up to about100 wt. % of the excess methanol is recaptured, purified, and reused fora subsequent esterification or transesterification. In specificembodiments, at least about 70 wt. % of the excess methanol isrecaptured, purified, and reused for a subsequent esterification ortransesterification. In more specific embodiments, at least about 80 wt.% of the excess methanol is recaptured, purified, and reused for asubsequent esterification or transesterification. In further specificembodiments, at least about 95 wt. % of the excess methanol isrecaptured, purified, and reused for a subsequent esterification ortransesterification.

Transesterification of Triglycerides

The transesterification process described herein converts triglycerides(with methanol as reagent, and solid heterogeneous transesterificationcatalyst) into biodiesel and glycerin. The transesterification processdescribed herein can include a two stage process, with intermediateglycerin settling. The first stage converts about 80 wt. % of the oil(triglycerides), and the second stage converts the remaining approximate20 wt. % of the oil.

Esterified oil from the esterification process described herein can bemixed with methanol (which is about 15% molar excess than thestoichiometric requirements). Pre-mixed raw materials enter the firststage reactor at a temperature of about 95° F., with a retention time ofabout 30 minutes. The resultant stream enters a settling tank wherebiodiesel (along with unreacted oil) is allowed to separate fromglycerin (about 4 hours residence time). The biodiesel stream (withunreacted oil) is separated and is allowed to flow from top of thesettling tank into the second stage reactor, where it is premixed withmethanol (about 15% molar excess).

In the second stage, the remaining oil reacts with methanol at about 95°F. and about 30-45 minutes residence time in the presence of the enzymecatalyst, producing biodiesel and glycerin. The outgoing stream enters asettling tank where the glycerin settles as the bottom layer after about4 hours of residence time, and the biodiesel stream overflows from thetop. Glycerin separated from the two settling tanks are sent to aglycerin purification unit where excess methanol is flashed off andrectified to about 99.8 wt. % purity. Glycerin of a minimum of about99.7% purity is obtained.

The biodiesel leaving the settling tank passes through a coalescer wheretrace amounts of glycerin is separated from the biodiesel. Biodieselleaving the coalescer contains traces of glycerol (less than about 200ppm), which goes to the final stage of purification with ion resins. Theresins adsorb free glycerol and brings the biodiesel to acceptablelevels of ASTM D6751 standards. Biodiesel further passes through adistillation column to remove or separate excess methanol and producesbiodiesel that has methanol content down to about 2000 pm or less.

Post-transesterification processing can involve a distillation processto effectively remove or separate the contaminants (e.g., sterols,monoglycerides, diglycerides, triglycerides, sulfur, phosphorus, primaryand secondary oxidation products, etc.) from the finished biodiesel,thereby producing a superior quality fuel. These contaminants are knownto affect the cloud point and cold soak test results on finishedbiodiesel as per ASTM D6751. Biodiesel resulting from this cold soak hasa filtration time of about 200 seconds or less. Biodiesel leaving thecold soak columns can now be analyzed per ASTM D6751 testing standardsand once passed is sent to the tank farm for storage.

Glycerin from the settling tanks can first be distilled to remove orseparate water and methanol from the glycerin. Relatively clean glycerolcan now be sent to a distillation column, where the glycerin isdistilled off at relatively high temperatures and under vacuum, to yielda colorless, about 99.7 wt. % pure technical grade glycerin. It can bepassed through bed of activated carbon to filter impurities before beingsent to the tank farm.

Referring to FIG. 6, a process flow diagram is provided for thetransesterification of triglycerides (601), present within a biodieselfeedstock (603). Briefly stated, triglycerides present in the biodieselfeedstock (603) are transesterified (615). Specifically, the biodieselfeedstock (603) is contacted (609) with a transesterifying reagent andcatalyst, to provide a transesterification reaction product (617) thatincludes the desired product biodiesel, the desired product glycerin,and by-product water. When a stoichiometric excess (e.g., 1.25 molarequivalent) of methanol is employed as the transesterifying reagent, thetransesterification reaction product (617) will typically includeunreacted methanol. The transesterification reaction product (617) isseparated (619) to provide biodiesel (623), and a mixture (621) ofmethanol, water and glycerin.

If the biodiesel contains a significant and appreciable amount oftriglycerides (633), the biodiesel (633) is contacted with methanol andtransesterification catalyst to form a subsequent transesterificationmixture (611), which is subject to transesterification conditions (615),to transesterify triglycerides (633) present therein. The subsequenttransesterifying (615) is carried out on the triglycerides presentwithin the subsequent transesterification mixture (611), to provide asubsequent transesterification product (617). The subsequenttransesterification product (617) is separated (619), to providesubsequent biodiesel (623), and a subsequent mixture (621) of methanol,water and glycerin. If the subsequent biodiesel (623) contains asignificant and appreciable amount of triglycerides (633), thetransesterification process is carried out until a subsequent biodiesel(623) does not contain a significant and appreciable amount oftriglycerides (633). Once this occurs, the one or more biodiesels (623)will be considered to be a purified biodiesel (639).

The one or more mixtures (621) of methanol, water and glycerin isseparated (627), to provide glycerin (633) and a mixture (625) ofmethanol and water. The glycerin (633) can be purified (635) (e.g.,distilled) to provide purified glycerin (643). Additionally, the mixture(625) of methanol and water can be distilled (637) to provide purifiedmethanol (641), which can be reused (613) in a subsequent esterificationreaction and/or transesterification reaction.

Referring to FIG. 3, a process flow diagram is provided for thetransesterification of triglycerides (301). Briefly stated, a biodieselfeedstock (303) is contacted (302) with a reagent (e.g., methanol) andcatalyst, to provide a mixture (305) that includes a biodieselfeedstock, methanol, and solid heterogeneous catalyst. The biodieselfeedstock (303) can include the biodiesel (217) obtained in theesterification (not shown, see FIG. 2). The mixture (305) that includesa biodiesel feedstock, methanol, and solid heterogeneous catalyst issubject to transesterification conditions (306), to provide a reactionproduct (315) that includes biodiesel, glycerin, water, and methanol.The reaction product (315) that includes biodiesel, glycerin, water, andmethanol is separated (314) into biodiesel (317) and a mixture (340) ofglycerin, water, and methanol. The biodiesel (317) is purified, bydistilling (320), to provide a purified biodiesel (331). The mixture(340) of glycerin, water, and methanol is separated (342) to providemixture (341) of water and methanol, which is distilled (318) to providepurified methanol (325). The purified methanol (325) is reused to form amixture (305).

The mixture (305) that includes a biodiesel feedstock, methanol, andsolid heterogeneous catalyst is transesterified (308), to provide areaction product (307), that includes biodiesel, glycerin, methanol,water, and triglycerides. The reaction product (307) is separated into amixture (309) of methanol and water, and a reaction product (311) thatincludes biodiesel and triglycerides. The mixture (309) is separated(312) into a mixture (341) of methanol and water, and glycerin (319).The reaction product (311) can contact (302) reagent and catalyst, toprovide the mixture (305), which is subject to transesterificationconditions (308), to provide reaction product (307), which is separated(310), to provide reaction product (311) and mixture (309). This processis repeated (316), one or more times, until the finaltransesterification (306) provides reaction product (315).

Each step of the transesterification of triglycerides (301) canindependently be carried out in a continuous fashion, in a batch mode,or in a semi-continuous mode or semi batch mode.

Transesterifying

Mixture (305) that includes biodiesel feedstock, methanol, and solidheterogeneous catalyst is subject to transesterification (306 or 308)conditions. The biodiesel feedstock (303) and the biodiesel feedstockpresent in mixture (305) can each include triglycerides. Thesetriglycerides present in biodiesel feedstock are transesterified withthe methanol, with the aid of the solid heterogeneous catalyst, toprovide biodiesel.

Mixture (305) is subject to transesterification (306 or 308) conditions,to provide reaction product (315) that includes biodiesel, water,methanol, and triglycerides. Alternatively, mixture (305) is subject totransesterification (306 or 308) conditions, to provide reaction product(307) that includes biodiesel, glycerin, water, methanol, andtriglycerides. When mixture (305) is subject to transesterification (306or 308) conditions, to provide reaction product (307), mixture (309)that includes methanol, glycerin, and water is separated (310) from thereaction product (307), to provide reaction product (311) that includesbiodiesel and triglycerides. Reaction product (311) is subsequentlycontacted (302) with reagent and catalyst, to form mixture (305), whichis subject to transesterification conditions (308). This process(transesterification (308) and separation (310)) is optionally repeated(316) one or more times, until the final transesterifying (306)substantially provides reaction product (315).

The transesterifying (306 or 308) can be carried out under suitabletransesterification conditions. Typically, the transesterification (306or 308) can be carried out at an elevated temperature. In specificembodiments, the methanol, catalyst, and biodiesel feedstock are heatedto a temperature of at least about 170° F. (76.67° C.). In furtherspecific embodiments, the methanol, catalyst, and biodiesel feedstockare heated to a temperature of up to about 200° F. (93.33° C.). Infurther specific embodiments, the methanol, catalyst, and biodieselfeedstock are heated to a temperature of between about 170° F. (76.67°C.) to about 200° F. (93.33° C.).

The transesterifying (306 or 308) can be carried out at an elevatedpressure. In specific embodiments, the methanol, catalyst, and biodieselfeedstock are heated at a pressure of at least about 15 psi (1.02 atm).In further specific embodiments, the methanol, catalyst, and biodieselfeedstock are heated at a pressure of up to about 50 psi (3.40 atm).

The transesterifying (306 or 308) is carried out for a requisite periodof time. In specific embodiments, the methanol, catalyst, and biodieselfeedstock are heated for a period of time of at least about 15 minutes.In further specific embodiments, the methanol, catalyst, and biodieselfeedstock are heated for a period of time of up to about 75 minutes. Infurther specific embodiments, the methanol, catalyst, and biodieselfeedstock are heated for a period of time of about 15 minutes to about75 minutes.

When the transesterifying (306 or 308) is carried out on a commercial orindustrial scale, the reagent can be employed in a molar orstoichiometric excess. This will assist in driving the reaction tocompletion. This is especially so when the transesterifying (308) andseparating (310) are carried out one or more times, thereby removing orseparating water from each of the one or more reaction products. Withthe transesterifying (306 or 308) described herein, the methanol can beemployed in a molar or stoichiometric excess, relative to thetriglycerides content of the biodiesel feedstock.

In specific embodiments, the methanol is employed in at least a 5 molaror stoichiometric excess, relative to the triglycerides content of thebiodiesel feedstock. In further specific embodiments, the methanol isemployed in at least a 10 molar or stoichiometric excess, relative tothe triglycerides content of the biodiesel feedstock. In furtherspecific embodiments, the methanol is employed in at least a 20 molar orstoichiometric excess, relative to the triglycerides content of thebiodiesel feedstock. In further specific embodiments, the methanol isemployed in up to a 100 molar or stoichiometric excess, relative to thetriglycerides content of the biodiesel feedstock.

The transesterifying (306 or 308) provides a reaction product (315 or307) that aside from water and glycerin, includes relatively fewby-products. In specific embodiments, the transesterifying (306 or 308)provides a reaction product (315 or 307) that includes little or no(e.g., less than about 0.5 wt. %) by-product.

The transesterifying (306 or 308) employs methanol as the reagent,present in mixture (305). The methanol will have a requisite purity. Forexample, in specific embodiments, the methanol will have a purity of atleast about 99 wt. %, at least about 99.5 wt. %, at least about 99.9 wt.%, or at least about 99.95 wt. %. In further specific embodiments, themethanol will have a purity of up to about 100 wt. %. Employing methanolhaving a requisite purity, within the transesterifying (306 or 308),will assist in driving the transesterification (306 or 308) tocompletion, while providing a relatively high yield and/or purity ofdesired product.

The transesterifying (306 or 308) employs a solid heterogeneouscatalyst, present in the mixture (305). In specific embodiments, thesolid heterogeneous catalyst includes Biocatalyst A solid catalyst,Biocatalyst B solid catalyst, or a combination thereof (TransBiodiesel,Israel). In specific embodiments, the solid heterogeneous catalyst isimmobilized on a solid support. In specific embodiments, the solidheterogeneous catalyst is non-toxic and is suitable for safely disposalin a land fill. It is believed that by employing a biodiesel (217) asthe biodiesel feedstock (303), the commercial life of the solidheterogeneous catalyst will be extended. This can lower the actual costof the solid heterogeneous catalyst, as well as the labor costs and costof down-time associated with replacing the solid heterogeneous catalyst.

In specific embodiments, the solid heterogeneous catalyst is active inthe transesterification (306 or 308) for at least about 6 months. Infurther specific embodiments, the solid heterogeneous catalyst is activein the transesterification (306 or 308) for at least about 12 months. Infurther specific embodiments, the solid heterogeneous catalyst is activein the transesterification (306 or 308) for up to about 18 months.

The transesterifying (308) can be repeated (316) one or more times. Assuch, the mixture (305) can be subjected to transesterification (308)conditions, to provide reaction product (307), which can be separatedinto mixture (309) and reaction product (311). Reaction product (311)can subsequently be contacted (302) with reagent and catalyst, to formmixture (305), which can be subjected to transesterification (308)conditions.

The transesterifying (306) is carried out one time. Additionally, thetransesterifying (308) is carried out zero or more times. When carriedout two or more times, the transesterifying (308) is repeated (316) zeroor more times and the transesterifying (306) is carried out one time. Inspecific embodiments, the transesterifying (308) is carried out about0-25 times, about 1-15 times, about 1-10 times, or about 1-5 times. Inmore specific embodiments, the transesterifying (308) is carried out atleast about 1 time, at least about 2 times, or at least about 3 times.

In specific embodiments, the repeating (316) is carried out until thefinal transesterifying (306) substantially provides reaction product(315). In more specific embodiments, the repeating (316) is carried outuntil the final transesterifying (306) substantially provides reactionproduct (315), that includes little or no (e.g., less than about 5 wt.%) triglycerides. In further specific embodiments, the repeating (316)is carried out until the final transesterifying (306) provides reactionproduct (315), that includes less than about 1 wt. % triglycerides. Infurther specific embodiments, the repeating (316) is carried out untilthe final transesterifying (306) provides reaction product (315), thatincludes less than about 0.5 wt. % triglycerides. In further specificembodiments, the repeating (316) is carried out until the finaltransesterifying (306) provides reaction product (315), that includesless than about 0.1 wt. % triglycerides.

In specific embodiments, the transesterifying (306 or 308) is carriedout in a batch mode. Alternatively, in specific embodiments, thetransesterifying (306 or 308) is carried out in a continuous fashion.

In specific embodiments, the transesterifying (306 or 308) iscontinuous, and can include a single stage reactor. In alternativespecific embodiments, the transesterifying (306 or 308) is continuous,and can include a multi-stage reactor (e.g., first stage reactor, secondstage reactor and third stage reactor). A multi-stage reactor is areference to transesterifying (306) and one or more transesterifyings(308), in FIG. 3.

When a multi-stage reactor is employed, each stage independentlyprovides for the conversion of triglycerides and methanol to biodiesel,glycerin, and water. In specific embodiments, each stage provides aconversion of at least about 80 wt. % of triglycerides present therein,to biodiesel, glycerin, and water. In more specific embodiments, eachstage provides a conversion of at least about 90 wt. % of triglyceridespresent therein, to biodiesel, glycerin, and water. In further specificembodiments, each stage provides a conversion of at least about 95 wt. %of triglycerides present therein, to biodiesel, glycerin, and water.Additionally, the single stage (or multi stage) reactor can beconfigured to operate at elevated temperature and/or at elevatedpressure.

The transesterifying (306 or 308) can independently be carried out on acommercial or industrial scale. For example, the transesterifying (306and 308) can be carried out to provide at least about 100 gallons ofcombined reaction product (307 and 315). Specifically, thetransesterifying (306 and 308) can be carried out to provide, withinabout 24 hours, at least about 100 gallons of combined reaction product(307 and 315). Additionally, the transesterifying (306 and 308) can becarried out to provide at least about 1,000 gallons of combined reactionproduct (307 and 315). Specifically, the transesterifying (306 and 308)can be carried out to provide, within about 24 hours, at least about1,000 gallons of combined reaction product (307 and 315).

When the transesterifying (306 or 308) is carried out as describedherein, the triglycerides are transesterified with methanol, with arelatively high conversion. In specific embodiments, the triglyceridesare transesterified with methanol, with a combined conversion of atleast about 70 wt. %. In further specific embodiments, the triglyceridesare transesterified with methanol, with a combined conversion of atleast about 85 wt. %. In further specific embodiments, the triglyceridesare transesterified with methanol, with a combined conversion of atleast about 95 wt. %. In further specific embodiments, the triglyceridesare transesterified with methanol, with a combined conversion of atleast about 98 wt. %. In further specific embodiments, the triglyceridesare transesterified with methanol, with a combined conversion of atleast about 99 wt. %. In further specific embodiments, the triglyceridesare transesterified with methanol, with a combined conversion of up toabout 100 wt. %.

Separating/Distilling

Each of the reaction product (307), mixture (309), reaction product(315), and mixture (340) can be separated (310, 314, 312, and (342),respectively). For example, the reaction product (307) can be separated(310) to provide a mixture (309) of methanol and water, and reactionproduct (311) that includes biodiesel and triglycerides. The mixture(309) can be separated (312) to provide mixture (341) of methanol andwater, and glycerin (319). The reaction product (315) can be separated(314) to provide biodiesel (317), and mixture (340) of glycerin, water,and methanol. Mixture (340) can be separated (342) to provide mixture(341) of water and methanol. Each of the separations can independentlybe carried out, e.g., by employing distillation.

Each of the distillations in the transesterification of triglycerides(301) can independently be carried out under suitable conditions. Forexample, each of the distillations in the transesterification oftriglycerides (301) can independently be carried out at elevatedtemperatures and/or reduced pressures (e.g., under vacuum).Specifically, each of the distillations in the transesterification oftriglycerides (301) can independently be carried out at elevatedtemperatures, e.g., at about 60° C. to about 530° C. Specifically, eachof the distillations in the transesterification of triglycerides (301)can independently be carried out at reduced pressures, e.g., about 24 toabout 29.92 inches of mercury (Hg).

Each of the distillations in the transesterification of triglycerides(301) can independently be carried out one or more times. Each of thedistillations in the transesterification of triglycerides (301) canindependently be carried out about 1-5 times, about 1-4 times, about 1-3times, or about 1-2 times.

In specific embodiments, each of the distillations in thetransesterification of triglycerides (301) is independently carried outin a batch mode. Alternatively, in specific embodiments, each of thedistillations in the transesterification of triglycerides (301) isindependently carried out in a continuous fashion. In specificembodiments, any one or more of the distillations in thetransesterification of triglycerides (301) is independently continuous,and includes a single stage distillation column. In alternative specificembodiments, any one or more of the distillations in thetransesterification of triglycerides (301) is independently continuous,and includes a multi-stage distillation column. Additionally, each ofthe single stage (or multi stage) distillation column can independentlyoperate with or without vacuum.

Each of the distillations in the transesterification of triglycerides(301) can independently be carried out on a commercial or industrialscale. For example, any one or more of the distillations in thetransesterification of triglycerides (301) can independently be carriedout to provide at least about 100 gallons of distillate. Specifically,any one or more of the distillations in the transesterification oftriglycerides (301) can independently be carried out to provide, withinabout 24 hours, at least about 100 gallons of distillate. Additionally,any one or more of the distillations in the transesterification oftriglycerides (301) can independently be carried out to provide at leastabout 1,000 gallons of distillate. Specifically, any one or more of thedistillations in the transesterification of triglycerides (301) canindependently be carried out to provide, within about 24 hours, at leastabout 1,000 gallons of distillate.

Reuse of Methanol

The transesterification of triglycerides (301) is carried out withmethanol as the reagent. For example, reagent (i.e., methanol) andcatalyst are added to the biodiesel feedstock (303), to form mixture(305) that includes biodiesel feedstock, methanol, and solidheterogeneous catalyst. As described herein, mixture (305) is subject totransesterification (306 or 308) conditions, sufficient to transesterifytriglycerides present in the mixture (305). Upon transesterification(306 or 308) of triglycerides present in the mixture (305), reactionproduct (315 or 307, respectively) is obtained. Because a molar orstoichiometric excess of methanol is typically employed in thetransesterification (306 or 308), each of reaction products (315 and307) will typically include methanol. This methanol can be recaptured,purified, and reused for a subsequent transesterification (306 or 308),or esterification (see, FIG. 2).

Specifically, reaction product (315) can be separated, e.g., intobiodiesel (317) and a mixture (340) of water, methanol and glycerin. Themixture (340) can further be separated (342) to mixture (341) of waterand methanol. The mixture (341) of water and methanol can be distilled(318) to provide purified methanol (325), which can be reused (304).Likewise, methanol present in reaction product (307) can be separated(310), to provide, e.g., a mixture (309) that includes methanol andwater. Mixture (309) can be separated (312), to provide, e.g., mixture(341) of methanol and water, which can be distilled (318) to providepurified methanol (325), which can be reused (304). When a molar orstoichiometric excess of methanol is employed in the transesterification(306 or 308), each of reaction products (315 and 307) will typicallyinclude methanol. This excess methanol can be recaptured, purified, andreused for a subsequent transesterification (306 or 308), oresterification (see, FIG. 2). In specific embodiments, up to about 100wt. % of the excess methanol is recaptured, purified, and reused for asubsequent esterification or transesterification. In specificembodiments, at least about 70 wt. % of the excess methanol isrecaptured, purified, and reused for a subsequent esterification ortransesterification. In more specific embodiments, at least about 80 wt.% of the excess methanol is recaptured, purified, and reused for asubsequent esterification or transesterification. In further specificembodiments, at least about 95 wt. % of the excess methanol isrecaptured, purified, and reused for a subsequent esterification ortransesterification.

Enumerated Embodiments

Specific enumerated embodiments [1] to [201] provided below are forillustration purposes only, and do not otherwise limit the scope of thedisclosed subject matter, as defined by the claims. These enumeratedembodiments encompass all combinations, sub-combinations, and multiplyreferenced (e.g., multiply dependent) combinations described therein.

Pretreatment

[1.] The present invention provides for a method that includes:

(a) filtering a biodiesel feedstock, thereby removing or separatingsolid particles having a diameter up to 2 microns, to provide a filtrateand a retentate;

(b) separating at least one of moisture and water from the filtrate, toprovide a dried filtrate;

(c) distilling the dried filtrate, to provide a distillate and aresidue;

(d) distilling the distillate to provide a subsequent distillate andoptionally a subsequent residue; and;

(e) optionally repeating steps (c) and (d), one or more times, bydistilling the subsequent distillate, to obtain a final distillate.

[2.] The present invention also provides for the method of embodiment[1], wherein the biodiesel feedstock further includes at least one oftriglycerides, gums, soaps, detergents, unsaponifiables, phosphatides,metals, phosphorus, sulfur, sulfates, sulfonates, sulfides, polyaromatichydrocarbons, polychlorinated hydrocarbons, polyethylene, plant basedsterols, animal based sterols, moisture, and water.[3.] The present invention also provides for the method of any one ofembodiments [1]-[2], wherein the feedstock includes up to about 100 wt.% free fatty acids.[4.] The present invention also provides for the method of any one ofembodiments [1]-[2], wherein the feedstock includes about 0.2 wt. % toabout 100 wt. % free fatty acids.[5.] The present invention also provides for the method of any one ofembodiments [1]-[4], wherein the feedstock includes at least one offats, oils, and grease.[6.] The present invention also provides for the method of any one ofembodiments [1]-[4], wherein the feedstock includes at least one ofedible oils, inedible oils, fats, greases, oils produced frommicrobial/biological/biotechnology/fermentation/metabolic activity, orsimilar-based process, brown grease, trap grease, used cooking oil, usedcooking fat, animal fat, animal grease, and fatty acid distillate.[7.] The present invention also provides for the method of any one ofembodiments [1]-[4], wherein the feedstock includes at least one oftallow, pork fat, poultry fat, lard, choice white grease, algae oil,crude vegetable oils, soybean oil, corn oil, coffee oil, hemp oil,linseed oil, rice bran oil, jojoba oil, tall oil, mustard oil,distillers grain oil (DDG corn oil), Jatropha oil, camellia oil,rapeseed oil, canola oil, moring a oil, pongamia oil, sunflower oil,safflower oil, crude palm oil, palm kernel oil, palm fatty aciddistillate, palm sludge oil, coconut oil, and their derivatives(including genetically modified and otherwise).[8.] The present invention also provides for the method of any one ofembodiments [1]-[7], wherein at least about 90 wt. % of the solidparticles having a diameter of at least about 2 microns are separated,to provide the filtrate and the retentate.[9.] The present invention also provides for the method of any one ofembodiments [1]-[7], wherein up to about 100 wt. % of the solidparticles having a diameter of at least about 2 microns are separated,to provide the filtrate and the retentate.[10.] The present invention also provides for the method of any one ofembodiments [1]-[9], wherein the separating of the solid particles iscarried out employing multiple filters, each having a smaller porosityor mesh size relative to a previous filter.[11.] The present invention also provides for the method of any one ofembodiments [1]-[10], wherein the biodiesel feedstock includes elevatedlevels of at least one of water, sulfur, phosphorus, gums/lipids,sterols, calcium, magnesium, iron, copper, cobalt, manganese, nickel,sodium, potassium, chlorophyll, carotenoids, xanthophylls, proteins andcarbohydrates, aldehydes, ketones, carboxylic acids, perchloroethylene,polyaromatic hydrocarbons, polychlorinated hydrocarbons, polymerizedtriglycerides, pesticides, soaps, detergents, sulfonates, sulfates,phosphatides, phytosterols, sitosterols, cholesterol, sterol glucosides,and other colored bodies.[12.] The present invention also provides for the method of any one ofembodiments [1]-[11], wherein the feedstock includes up to about 20,000ppm of at least one of sulfur, sulfates, sulfides, and sulfonates.[13.] The present invention also provides for the method of any one ofembodiments [1]-[12], wherein the feedstock includes up to about 4000ppmw phosphorus.[14.] The present invention also provides for the method of any one ofembodiments [1]-[13], which separates from the feedstock at least one ofwater, sulfur, phosphorus, gums, strerols, calcium, magnesium, iron,copper, sodium, potassium, chlorophyll, phosphatides, and coloredbodies.[15.] The present invention also provides for the method of any one ofembodiments [1]-[14], wherein any one or more of the distillings iscarried out while heating the feedstock to a temperature of about 100°C. to about 530° C.[16.] The present invention also provides for the method of any one ofembodiments [1]-[14], wherein any one or more of the distillings iscarried out while heating the feedstock to a temperature of about 200°C. to about 230° C.[17.] The present invention also provides for the method of any one ofembodiments [1]-[16], wherein any one or more of the distillings iscarried out under vacuum, to about 24 to about 29.92 inches of mercury(Hg).[18.] The present invention also provides for the method of any one ofembodiments [1]-[16], wherein any one or more of the distillings iscarried out without vacuum.[19.] The present invention also provides for the method of any one ofembodiments [1]-[18], further including recycling the distillate with areflux ratio of about 0.2 to about 3.5.[20.] The present invention also provides for the method of any one ofembodiments [1]-[19], wherein relative to the distillate, the residue isenriched in at least one of sulfur, phosphorus, gums/lipids, sterols,calcium, magnesium, iron, copper, cobalt, manganese, nickel, sodium,potassium, chlorophyll, carotenoids, xanthophylls, proteins andcarbohydrates, aldehydes, ketones, carboxylic acids, perchloroethylene,polyaromatic hydrocarbons, polychlorinated hydrocarbons, polymerizedtriglycerides, pesticides, soaps, detergents, sulfonates, sulfates,phosphatides, phytosterols, sitosterols, cholesterol, sterol glucosides,oils and fats, other trace impurities, and other colored bodies.[21.] The present invention also provides for the method of any one ofembodiments [1]-[19], wherein relative to the residue, the distillate isenriched in at least one of triglycerides and free fatty acids.[22.] The present invention also provides for the method of any one ofembodiments [1]-[21], wherein the distillate includes up to about 99.995wt. % triglycerides and free fatty acids.[23.] The present invention also provides for the method of any one ofembodiments [1]-[22], wherein the distillate includes at least one oftriglycerides and free fatty acids, wherein the at least one oftriglycerides and free fatty acids combined include less than about 7ppm phosphorus, less than about 7 ppm sulfur, and less than about 10 ppmof all other metals combined.[24.] The present invention also provides for the method of any one ofembodiments [1]-[23], wherein the distillate includes at least one oftriglycerides and free fatty acids, wherein the at least one oftriglycerides and free fatty acids combined include less than about 7ppm sulfur.[25.] The present invention also provides for the method of any one ofembodiments [1]-[24], wherein a weight of the retentate is up to about0.2% a weight of the feedstock.[26.] The present invention also provides for the method of any one ofembodiments [1]-[25], wherein the retentate is non-toxic and suitablefor safe disposal in a land fill.[27.] The present invention also provides for the method of any one ofembodiments [1]-[26], wherein the weight of the residue is about 0.2% toabout 6% the weight of the dried filtrate.[28.] The present invention also provides for the method of any one ofembodiments [1]-[27], wherein distilling the one or more subsequentdistillates includes a single stage distillation column, operating withor without vacuum.[29.] The present invention also provides for the method of any one ofembodiments [1]-[28], wherein the continuously distilling includes amulti-stage distillation column.[30.] The present invention also provides for the method of any one ofembodiments [1]-[29], wherein at least about 100 gallons of biodieselfeedstock is employed.[31.] The present invention also provides for the method of any one ofembodiments [1]-[29], wherein up to about 1,000 gallons of biodieselfeedstock is employed.[32.] The present invention also provides for the method of any one ofembodiments [1]-[31], wherein at least about 100 gallons of thedistillate is obtained, within 24 hours.[33.] The present invention also provides for the method of any one ofembodiments [1]-[31], wherein up to about 1,000 gallons of thedistillate is obtained, within 24 hours.[34.] The present invention also provides for the method of any one ofembodiments [1]-[33], wherein prior to the process, the biodieselfeedstock is analyzed to determine a qualitative nature of impuritieslocated therein.[35.] The present invention also provides for the method of any one ofembodiments [1]-[33], wherein prior to the process, the biodieselfeedstock is analyzed to determine a quantitative nature of impuritieslocated therein.[36.] The present invention also provides for the method of any one ofembodiments [1]-[35], wherein the filtering is carried out in thepresence of an adsorbent.[37.] The present invention also provides for the method of any one ofembodiments [1]-[35], wherein the filtering is carried out in theabsence of an adsorbent.[38.] The present invention also provides for the method of any one ofembodiments [1]-[37], which is a method for separating from biodieselfeedstock at least one of water, sulfur, phosphorus, gums/lipids,sterols, calcium, magnesium, iron, copper, cobalt, manganese, nickel,sodium, potassium, chlorophyll, carotenoids, xanthophylls, proteins andcarbohydrates, aldehydes, ketones, carboxylic acids, perchloroethylene,polyaromatic hydrocarbons, polychlorinated hydrocarbons, polymerizedtriglycerides, pesticides, soaps, detergents, sulfonates, sulfates,phosphatides, phytosterols, sitosterols, cholesterol, sterol glucosides,oils and fats, other trace impurities, and other colored bodies.[39.] The present invention also provides for the method of any one ofembodiments [1]-[38], which does not include adding water.[40.] The present invention also provides for the method of any one ofembodiments [1]-[39], wherein the distillate and the residue areseparated.[41.] The present invention also provides for the method of any one ofembodiments [1]-[40], which is a method of purifying a biodieselfeedstock.[42.] The present invention also provides for the method of any one ofembodiments [1]-[41], wherein the distillate and the residue areseparated, and the distillate is subsequently distilled to provide thesubsequent distillate and the subsequent residue.[43.] The present invention also provides for the method of any one ofembodiments [1]-[41], wherein the distillate and the residue areseparated, the distillate is subsequently distilled to provide thesubsequent distillate and the subsequent residue, and the method isrepeated one or more times.[44.] The present invention also provides for the method of any one ofembodiments [1]-[41], wherein the distillate and the residue areseparated, the distillate is subsequently distilled to provide thesubsequent distillate and the subsequent residue, and the method isrepeated one or more times, until no appreciable or significant amountof residue is obtained.[45.] The present invention also provides for the method of any one ofembodiments [1]-[44], wherein the distillate and the residue areseparated, and the distillate is stored as a purified biodieselfeedstock.[46.] The present invention also provides for the method of any one ofembodiments [1]-[45], wherein the steps (c) and (d) are repeated, one ormore times, by distilling the subsequent distillate, to obtain a finaldistillate.[47.] The present invention also provides for the method of any one ofembodiments [1]-[46], wherein the steps (c) and (d) are repeated, two ormore times, by distilling the subsequent distillate, to obtain a finaldistillate.[48.] The present invention also provides for the method of any one ofembodiments [1]-[47], wherein the feedstock includes one or more of thefeedstock impurities illustrated in Table A.[49.] The present invention also provides for the method of any one ofembodiments [1]-[47], wherein the feedstock includes each of thefeedstock impurities illustrated in Table A.[50.] The present invention also provides for the method of any one ofembodiments [1]-[47], wherein the feedstock includes one or more of thefeedstock impurities illustrated in Table A, each in the amountdisclosed therein.[51.] The present invention also provides for the method of any one ofembodiments [1]-[47], wherein the feedstock includes each of thefeedstock impurities illustrated in Table A, each in the amountdisclosed therein.Esterification[52.] The present invention provides for a method including:

(a) contacting (i) methanol, (ii) a solid heterogeneous esterificationcatalyst, and (iii) a biodiesel feedstock including free fatty acids,wherein the contacting is carried out under conditions suitable toprovide an esterification reaction product including biodiesel,methanol, water, and optionally free fatty acids;

(b) separating water and methanol from the esterification reactionproduct;

(c) contacting the esterification reaction product with (i) methanol and(iii) a solid heterogeneous esterification catalyst, wherein thecontacting is carried out under conditions suitable to provide asubsequent esterification reaction product including biodiesel,methanol, water and optionally free fatty acids; and

(d) optionally repeating steps (b) and (c) one or more times, to providean esterification reaction product including biodiesel;

wherein the methanol separated from the one or more esterificationreaction products is purified to a purity of at least about 99.9 wt. %,and is employed in a subsequent esterification.

[53.] The present invention also provides for the method of embodiment[52], which is a method for esterifying, with methanol, free fatty acidspresent in a biodiesel feedstock.

[54.] The present invention also provides for the method of any one ofembodiments [52]-[53], wherein the biodiesel feedstock including freefatty acids includes a distillate obtained from a pretreatment process.

[55.] The present invention also provides for the method of any one ofembodiments [52]-[54], which is carried out in the absence of a toxicmineral acid.

[56.] The present invention also provides for the method of any one ofembodiments [52]-[55], which is carried out in the absence of phosphoricacid, sulfuric acid, hydrochloric acid, citric acid, or a combinationthereof.

[57.] The present invention also provides for the method of any one ofembodiments [52]-[56], wherein the free fatty acids are esterified withmethanol, with a conversion of at least about 70 wt. %.

[58.] The present invention also provides for the method of any one ofembodiments [52]-[56], wherein the free fatty acids are esterified withmethanol, with a conversion of up to about 100 wt. %.

[59.] The present invention also provides for the method of any one ofembodiments [52]-[58], wherein the free fatty acids are esterified withmethanol, with no soap product, no salt product, or any by-product.

[60.] The present invention also provides for the method of any one ofembodiments [52]-[59], wherein the solid heterogeneous catalyst lasts atleast about 6 months.

[61.] The present invention also provides for the method of any one ofembodiments [52]-[59], wherein the solid heterogeneous catalyst lasts upto about 18 months.

[62.] The present invention also provides for the method of any one ofembodiments [52]-[61], wherein the biodiesel feedstock, prior tocontacting the methanol, is pretreated to separate trace elements,impurities and foulants selected from gums, metals, cations, proteins,and phospholipids.[63.] The present invention also provides for the method of any one ofembodiments [52]-[62], wherein the biodiesel feedstock is premixed withmethanol, and prior to contacting the methanol, is pretreated atstandard temperature.[64.] The present invention also provides for the method of any one ofembodiments [52]-[62], wherein the biodiesel feedstock is not premixedwith methanol, and prior to contacting the methanol, is pretreated atstandard temperature.[65.] The present invention also provides for the method of any one ofembodiments [52]-[62], wherein the biodiesel feedstock is premixed withmethanol, and prior to contacting the methanol, is pretreated atstandard pressure.[66.] The present invention also provides for the method of any one ofembodiments [52]-[62], wherein the biodiesel feedstock is not premixedwith methanol, and prior to contacting the methanol, is pretreated atstandard pressure.[67.] The present invention also provides for the method of any one ofembodiments [52]-[66], wherein the biodiesel feedstock, prior tocontacting the methanol, is pretreated by passing through an ionexchange resin.[68.] The present invention also provides for the method of any one ofembodiments [52]-[66], wherein the biodiesel feedstock, prior tocontacting the methanol, is pretreated with an ion exchange resin, whichconsists of a straight, flow-through 2 stage guard bed column reactorsin series.[69.] The present invention also provides for the method of any one ofembodiments [52]-[68], wherein the solid heterogeneous catalyst includesa solid, heterogeneous, polymeric esterification catalyst.[70.] The present invention also provides for the method of any one ofembodiments [52]-[69], wherein the methanol, catalyst, and biodieselfeedstock are heated to a temperature of at least about 170° F. (76.67°C.).[71.] The present invention also provides for the method of any one ofembodiments [52]-[69], wherein the methanol, catalyst, and biodieselfeedstock are heated to a temperature of up to about 200° F. (93.33°C.).[72.] The present invention also provides for the method of any one ofembodiments [52]-[71], wherein the methanol, catalyst, and biodieselfeedstock are heated at a pressure of at least about 15 psi (1.02 atm).[73.] The present invention also provides for the method of any one ofembodiments [52]-[71], wherein the methanol, catalyst, and biodieselfeedstock are heated at a pressure of up to about 50 psi (3.40 atm).[74.] The present invention also provides for the method of any one ofembodiments [52]-[73], wherein the methanol, catalyst, and biodieselfeedstock are heated for a period of time of at least about 15 minutes.[75.] The present invention also provides for the method of any one ofembodiments [52]-[73], wherein the methanol, catalyst, and biodieselfeedstock are heated for a period of time of up to about 75 minutes.[76.] The present invention also provides for the method of any one ofembodiments [52]-[75], wherein the methanol is employed in astoichiometric excess, relative to the free fatty acid content of thebiodiesel feedstock.[77.] The present invention also provides for the method of any one ofembodiments [52]-[75], wherein the methanol is employed in up to about a100% molar excess, relative to the free fatty acid content of thebiodiesel feedstock.[78.] The present invention also provides for the method of any one ofembodiments [52]-[77], further including separating the water from thebiodiesel.[79.] The present invention also provides for the method of any one ofembodiments [52]-[77], further including separating the water from thebiodiesel by employing a flash column, with demister pads and undervacuum.[80.] The present invention also provides for the method of any one ofembodiments [52]-[79], further including separating un-reacted methanolfrom the biodiesel.[81.] The present invention also provides for the method of any one ofembodiments [52]-[79], further including separating un-reacted methanolfrom the biodiesel, by employing a flash column, with demister pads andunder vacuum.[82.] The present invention also provides for the method of any one ofembodiments [52]-[79], further including separating un-reacted methanolfrom the biodiesel, purifying the separated methanol to a purity of atleast about 99.9%, and employing the purified methanol in a subsequentbiodiesel esterification or biodiesel transesterification.[83.] The present invention also provides for the method of any one ofembodiments [52]-[82], which is carried out including a first stagereactor, a second stage reactor and a third stage reactor.[84.] The present invention also provides for the method of any one ofembodiments [52]-[82], which is carried out including a first stagereactor, a second stage reactor and a third stage reactor, wherein eachstage independently provides for the conversion of free fatty acids andmethanol to biodiesel and water.[85.] The present invention also provides for the method of any one ofembodiments [52]-[82], which is carried out including a first stagereactor, a second stage reactor and a third stage reactor, wherein eachstage independently provides for the conversion of free fatty acids andmethanol to biodiesel and water, with a conversion at each stage of atleast about 90 wt. %.[86.] The present invention also provides for the method of any one ofembodiments [52]-[82], which is carried out including a first stagereactor, wherein upon conversion of free fatty acid present in thebiodiesel feedstock to biodiesel, water and excess methanol areseparated from the reaction product.[87.] The present invention also provides for the method of any one ofembodiments [52]-[82], which is carried out including a first stagereactor, wherein upon conversion of free fatty acid present in thebiodiesel feedstock to biodiesel, water and methanol are separated fromthe reaction product, and the methanol is subsequently purified.[88.] The present invention also provides for the method of any one ofembodiments [52]-[82], which is carried out including a first stagereactor, wherein upon conversion of free fatty acid present in thebiodiesel feedstock to biodiesel, water and methanol are separated fromthe biodiesel, triglycerides, and un-reacted free fatty acids, andtransferred to a second stage reactor.[89.] The present invention also provides for the method of any one ofembodiments [52]-[88], further including transferring biodiesel,triglycerides, and un-reacted free fatty acids from a first stagereactor to a send stage reactor, wherein the biodiesel, triglycerides,and un-reacted free fatty acids include less than about 1 wt. % water.[90.] The present invention also provides for the method of any one ofembodiments [52]-[89], further including transferring biodiesel,triglycerides, and un-reacted free fatty acids from a first stagereactor to a second stage reactor, wherein the biodiesel, triglycerides,and un-reacted free fatty acids include less than about 1 wt. %methanol.[91.] The present invention also provides for the method of any one ofembodiments [52]-[90], further including transferring biodiesel,triglycerides, and un-reacted free fatty acids from a first stagereactor to a second stage reactor, and contacting with methanol having apurity of at least about 98 wt. % pure.[92.] The present invention also provides for the method of any one ofembodiments [52]-[91], further including transferring biodiesel,triglycerides, and un-reacted free fatty acids from a first stagereactor to a second stage reactor, and contacting with a stoichiometricexcess of methanol, relative to the free fatty acid content of thebiodiesel.[93.] The present invention also provides for the method of any one ofembodiments [52]-[91], further including transferring biodiesel,triglycerides, and un-reacted free fatty acids from a first stagereactor to a second stage reactor, and contacting with up to about a100% molar excess of methanol, relative to the free fatty acid contentof the biodiesel.[94.] The present invention also provides for the method of any one ofembodiments [52]-[93], wherein the biodiesel includes less than about 1wt. % free fatty acid.[95.] The present invention also provides for the method of any one ofembodiments [52]-[94], wherein the biodiesel further includestriglycerides.[96.] The present invention also provides for the method of any one ofembodiments [52]-[95], wherein the water is separated from thebiodiesel, such that the biodiesel includes less than about 1.5 wt. %water.[97.] The present invention also provides for the method of any one ofembodiments [52]-[96], wherein un-reacted methanol is separated from thebiodiesel, such that the biodiesel includes less than about 1.5 wt. %methanol.[98.] The present invention also provides for the method of any one ofembodiments [52]-[97], which provides for a crude reaction productincluding water, methanol, biodiesel, triglycerides and free fatty acid.[99.] The present invention also provides for the method of any one ofembodiments [52]-[98], which provides for a crude reaction productincluding water, methanol, biodiesel, triglycerides and free fatty acid;and the method further including separating at least one of water andmethanol from the crude reaction product.[100.] The present invention also provides for the method of any one ofembodiments [52]-[99], which provides for a crude reaction productincluding water, methanol, biodiesel, triglycerides and free fatty acid;and the method further including separating at least one of water andmethanol from the crude reaction product under vacuum of 29.92 inches ofmercury (Hg), or less.[101.] The present invention also provides for the method of any one ofembodiments [52]-[100], which provides for a crude reaction productincluding water, methanol, biodiesel, triglycerides and free fatty acid;and the method further including separating at least one of water andmethanol from the crude reaction product at a temperature of at leastabout 170° F. (76.67° C.).[102.] The present invention also provides for the method of any one ofembodiments [52]-[101], which provides for a crude reaction productincluding water, methanol, biodiesel, triglycerides and free fatty acid,and wherein the biodiesel and triglycerides are not subsequentlyseparated from one another.[103.] The present invention also provides for the method of any one ofembodiments [52]-[102], wherein at least about 100 gallons of biodieselfeedstock is employed.[104.] The present invention also provides for the method of any one ofembodiments [52]-[102], wherein up to about 1,000 gallons of biodieselfeedstock is employed.[105.] The present invention also provides for the method of any one ofembodiments [52]-[104], wherein at least about 100 gallons of biodieselis obtained, within 24 hours.[106.] The present invention also provides for the method of any one ofembodiments [52]-[104], wherein up to about 1,000 gallons of biodieselis obtained, within 24 hours.[107.] The present invention also provides for the method of any one ofembodiments [52]-[106], wherein the catalyst is non-toxic and suitablefor safely disposal in a land fill.[108.] The present invention also provides for the method of any one ofembodiments [52]-[107], wherein the catalyst is immobilized on a solidsupport.[109.] The present invention also provides for the method of any one ofembodiments [52]-[108], wherein the methanol is obtained from a previousesterification.[110.] The present invention also provides for the method of any one ofembodiments [52]-[109], carried out in a continuous fashion.[111.] The present invention also provides for the method of any one ofembodiments [52]-[110], carried out in a batch mode.[112.] The present invention also provides for the method of any one ofembodiments [52]-[111], wherein the free fatty acids present in thebiodiesel feedstock are esterified with methanol to provide a reactionproduct including biodiesel, water, triglycerides, and un-reactedmethanol.[113.] The present invention also provides for the method of any one ofembodiments [52]-[111], wherein the free fatty acids present in thebiodiesel feedstock are esterified with methanol to provide a reactionproduct including biodiesel, water, triglycerides, un-reacted methanol,and un-reacted free fatty acids.[114.] The present invention also provides for the method of any one ofembodiments [52]-[111], wherein the free fatty acids present in thebiodiesel feedstock are esterified with methanol to provide a reactionproduct including biodiesel, water, triglycerides, un-reacted methanol,and un-reacted free fatty acids; and at least one of water and methanolare separated from the reaction product.[115.] The present invention also provides for the method of any one ofembodiments [52]-[111], wherein the free fatty acids present in thebiodiesel feedstock are esterified with methanol to provide a reactionproduct including biodiesel, water, triglycerides, un-reacted methanol,and un-reacted free fatty acids;

at least one of water and methanol are separated from the reactionproduct; and

-   -   the reaction product including biodiesel, triglycerides, and        free fatty acids is subsequently esterified to provide a        subsequent reaction product including biodiesel, water,        triglycerides, un-reacted methanol, and optionally free fatty        acids.        [116.] The present invention also provides for the method of any        one of embodiments [52]-[111], wherein the free fatty acids        present in the biodiesel feedstock are esterified with methanol        to provide a reaction product including biodiesel, water,        triglycerides, un-reacted methanol, and un-reacted free fatty        acids;

at least one of water and methanol are separated from the reactionproduct;

-   -   the reaction product including biodiesel, triglycerides, and        free fatty acids is subsequently esterified to provide a        subsequent reaction product including biodiesel, water,        triglycerides, un-reacted methanol, and optionally free fatty        acids; and    -   the separation and esterification are optionally repeated one or        more times until a further subsequent reaction product does not        include a significant or appreciable amount of free fatty acids.        [117.] The present invention also provides for the method of any        one of embodiments [114]-[116], wherein both water and methanol        are separated from the one or more esterification reaction        products.        [118.] The present invention also provides for the method of any        one of embodiments [52]-[117], wherein the biodiesel feedstock        including free fatty acids includes the final distillate of any        one of embodiments [1]-[51].        Transesterification        [119.] The present invention provides for a method including:

(a) contacting at a temperature of less than 102° F. (38.89° C.) (i)methanol, (ii) a solid heterogeneous transesterification catalyst, and(iii) a biodiesel feedstock including triglycerides, wherein thecontacting is carried out under conditions suitable to provide abiodiesel, methanol, water, glycerin and optionally triglycerides;

(b) separating water, glycerin and methanol from the transesterificationreaction product;

(c) contacting the transesterification reaction product with (i)methanol and (ii) a solid heterogeneous transesterification catalyst,wherein the contacting is carried out under conditions suitable toprovide a subsequent transesterification reaction product includingbiodiesel, methanol, water, glycerin and optionally triglycerides; and

(d) optionally repeating steps (b) and (c) one or more times, to providea transesterification reaction product including biodiesel and glycerin;

wherein the methanol separated from the one or more transesterificationreaction products is purified to a purity of at least about 99.9 wt. %,and is employed in a subsequent transesterification.

[120.] The present invention also provides for the method of embodiment[119], which is a method for transesterifying, with methanol,triglycerides present in a biodiesel feedstock.

[121.] The present invention also provides for the method of any one ofembodiments [119]-[120], wherein the catalyst is a transesterificationenzyme catalyst.

[122.] The present invention also provides for the method of any one ofembodiments [119]-[121], wherein the biodiesel feedstock includingtriglycerides includes an esterification reaction product includingbiodiesel.

[123.] The present invention also provides for the method of any one ofembodiments [119]-[122], wherein the catalyst is non-toxic and suitablefor safe disposal in a land fill.

[124.] The present invention also provides for the method of any one ofembodiments [119]-[123], wherein the catalyst is an enzyme biocatalyst.

[125.] The present invention also provides for the method of any one ofembodiments [119]-[124], wherein the catalyst is immobilized on a solidsupport.

[126.] The present invention also provides for the method of any one ofembodiments [119]-[125], wherein the catalyst has a stability such thatless than about 5 wt. % will degrade at standard temperature andpressure within 1 year.

[127.] The present invention also provides for the method of any one ofembodiments [119]-[126], wherein the contacting is carried out at atemperature of 95° F. (35° C.), ±6° F.

[128.] The present invention also provides for the method of any one ofembodiments [119]-[127], carried out in the absence of sodium methylate.

[129.] The present invention also provides for the method of any one ofembodiments [119]-[128], wherein the reaction mixture includingmethanol, biodiesel feedstock and heterogeneous solid catalystoptionally further includes up to about 1 wt. % water.

[130.] The present invention also provides for the method of any one ofembodiments [119]-[129], which includes a first stage reactor and asecond stage reactor.

[131.] The present invention also provides for the method of any one ofembodiments [119]-[130], wherein the methanol is employed in astoichiometric excess, relative to the triglycerides content of thebiodiesel feedstock.

[132.] The present invention also provides for the method of any one ofembodiments [119]-[130], wherein the methanol is employed in up to abouta 20% molar excess, relative to the triglycerides content of thebiodiesel feedstock.

[133.] The present invention also provides for the method of any one ofembodiments [119]-[132], wherein the methanol, catalyst, and biodieselfeedstock are heated for a period of time of at least about 15 minutes.

[134.] The present invention also provides for the method of any one ofembodiments [119]-[132], wherein the methanol, catalyst, and biodieselfeedstock are heated for a period of time of up to about 75 minutes.

[135.] The present invention also provides for the method of any one ofembodiments [119]-[134], which provides for a crude reaction productincluding biodiesel, triglycerides, glycerin, methanol, and water;

the method further including separating at least one of methanol andwater from the crude reaction product.

[136.] The present invention also provides for the method of any one ofembodiments [119]-[134], which provides for a crude reaction productincluding biodiesel, triglycerides, glycerin, methanol, and water;

the method further including separating at least one of methanol andwater from the crude reaction product and purifying the methanol.

[137.] The present invention also provides for the method of any one ofembodiments [119]-[134], which provides for a crude reaction productincluding biodiesel, triglycerides, glycerin, methanol, and water;

the method further including separating at least one of methanol andwater from the crude reaction product, purifying the methanol, andreusing the purified methanol in a subsequent transesterification.

[138.] The present invention also provides for the method of any one ofembodiments [119]-[136], which provides for a crude reaction productincluding biodiesel, triglycerides, glycerin, methanol, and water;

the method further including separating triglycerides from the crudereaction product.

[139.] The present invention also provides for the method of any one ofembodiments [119]-[136], which provides for a crude reaction productincluding biodiesel, triglycerides, glycerin, methanol, and water;

the method further including separating triglycerides from the crudereaction product and transferring the triglycerides to a second stagereactor and contacting the triglycerides with methanol having a purityof at least about 98 wt. % pure.

[140.] The present invention also provides for the method of any one ofembodiments [119]-[136], which provides for a crude reaction productincluding biodiesel, triglycerides, glycerin, methanol, and water;

the method further including separating biodiesel and triglycerides fromthe crude reaction product and transferring the biodiesel andtriglycerides to a second stage reactor and contacting the biodiesel andtriglycerides with methanol having a purity of at least about 98 wt. %pure.

[141.] The present invention also provides for the method of any one ofembodiments [119]-[140], wherein the methanol is obtained from aprevious transesterification.

[142.] The present invention also provides for the method of any one ofembodiments [119]-[141], which provides for a crude reaction productincluding biodiesel, triglycerides, glycerin, methanol, and water;

the method further including separating glycerin from the crude reactionproduct.

[143.] The present invention also provides for the method of any one ofembodiments [119]-[142], further including purifying the biodiesel.

[144.] The present invention also provides for the method of any one ofembodiments [119]-[142], further including purifying the biodiesel fromat least one of water, methanol, glycerol, sterols, monoglycerides,diglycerides, and triglycerides.

[145.] The present invention also provides for the method of any one ofembodiments [119]-[144], wherein at least about 90 wt. % of thetriglycerides present in the biodiesel feedstock are converted to thebiodiesel.

[146.] The present invention also provides for the method of any one ofembodiments [119]-[144], wherein up to about 100 wt. % of thetriglycerides present in the biodiesel feedstock are converted to thebiodiesel.

[147.] The present invention also provides for the method of any one ofembodiments [119]-[146], wherein the biodiesel is at least about 99 wt.% pure.

[148.] The present invention also provides for the method of any one ofembodiments [119]-[147], wherein the biodiesel includes less than about2,000 ppmw of methanol.

[149.] The present invention also provides for the method of any one ofembodiments [119]-[148], wherein the biodiesel includes less than about0.24 wt. % of total glycerol.

[150.] The present invention also provides for the method of any one ofembodiments [119]-[148], wherein the biodiesel includes less than about0.18 wt. % of total glycerol.

[151.] The present invention also provides for the method of any one ofembodiments [119]-[148], wherein the biodiesel includes no more thanabout 0.12 wt. % of total glycerol.

[152.] The present invention also provides for the method of any one ofembodiments [119]-[148], wherein the biodiesel includes less than about0.05 wt. % of free glycerin.

[153.] The present invention also provides for the method of any one ofembodiments [119]-[148], wherein the biodiesel includes less than about300 ppmw of free glycerin.

[154.] The present invention also provides for the method of any one ofembodiments [119]-[148], wherein the biodiesel includes no more thanabout 200 ppmw of free glycerin.

[155.] The present invention also provides for the method of any one ofembodiments [119]-[154], wherein the biodiesel includes less than about0.5 acid number.

[156.] The present invention also provides for the method of any one ofembodiments [119]-[154], wherein the biodiesel includes less than about0.4 acid number.

[157.] The present invention also provides for the method of any one ofembodiments [119]-[154], wherein the biodiesel includes no more thanabout 0.2 acid number.

[158.] The present invention also provides for the method of any one ofembodiments [119]-[157], wherein the biodiesel has a flash point of atleast about 120° C.

[159.] The present invention also provides for the method of any one ofembodiments [119]-[157], wherein the biodiesel has a flash point of atleast about 150° C.

[160.] The present invention also provides for the method of any one ofembodiments [119]-[157], wherein the biodiesel has a flash point of atleast about 170° C.

[161.] The present invention also provides for the method of any one ofembodiments [119]-[160], wherein the biodiesel has a moisture content ofless than about 200 ppmw.

[162.] The present invention also provides for the method of any one ofembodiments [119]-[160], wherein the biodiesel has a moisture content ofno more than about 50 ppmw.

[163.] The present invention also provides for the method of any one ofembodiments [119]-[162], wherein the biodiesel has a sulfur content thatis less than about 15 ppm.

[164.] The present invention also provides for the method of any one ofembodiments [119]-[162], wherein the biodiesel has a sulfur content thatis less than about 10 ppm.

[165.] The present invention also provides for the method of any one ofembodiments [119]-[162], wherein the biodiesel has a sulfur content thatis less than about 5 ppm.

[166.] The present invention also provides for the method of any one ofembodiments [119]-[165], wherein the biodiesel has a phosphorus contentthat is less than about 15 ppm.

[167.] The present invention also provides for the method of any one ofembodiments [119]-[165], wherein the biodiesel has a phosphorus contentthat is less than about 10 ppm.

[168.] The present invention also provides for the method of any one ofembodiments [119]-[165], wherein the biodiesel has a phosphorus contentthat is less than about 5 ppm.

[169.] The present invention also provides for the method of any one ofembodiments [119]-[168], wherein the biodiesel has a content ofpolymerized triglycerides that is less than about 15 ppm.

[170.] The present invention also provides for the method of any one ofembodiments [119]-[169], wherein the biodiesel has a content ofpolymerized triglycerides that is less than about 10 ppm.

[171.] The present invention also provides for the method of any one ofembodiments [119]-[170], wherein the biodiesel has a content ofpolymerized triglycerides that is less than about 5 ppm.

[172.] The present invention also provides for the method of any one ofembodiments [119]-[171], wherein the biodiesel has a sterols contentthat is less than about 25 ppm.

[173.] The present invention also provides for the method of any one ofembodiments [119]-[171], wherein the biodiesel has a sterols contentthat is less than about 15 ppm.

[174.] The present invention also provides for the method of any one ofembodiments [119]-[171], wherein the biodiesel has a sterols contentthat is less than about 10 ppm.

[175.] The present invention also provides for the method of any one ofembodiments [119]-[174], carried out in a continuous fashion.

[176.] The present invention also provides for the method of any one ofembodiments [119]-[174], carried out in a batch mode.

[177.] The present invention also provides for the method of any one ofembodiments [119]-[176], wherein any triglycerides, diglycerides, andmonoglycerides present in the biodiesel feedstock are transesterifiedwith methanol, to provide a reaction product including biodiesel,glycerin, water, and un-reacted methanol.[178.] The present invention also provides for the method of any one ofembodiments [119]-[176], wherein any triglycerides, diglycerides, andmonoglycerides present in the biodiesel feedstock are transesterifiedwith methanol, to provide a reaction product including biodiesel,glycerin, water, un-reacted methanol, and optionally un-reactedtriglycerides.[179.] The present invention also provides for the method of any one ofembodiments [119]-[176], wherein any triglycerides, diglycerides, andmonoglycerides present in the biodiesel feedstock are transesterifiedwith methanol, to provide a reaction product including biodiesel,glycerin, water, un-reacted methanol, and optionally un-reactedtriglycerides; and at least one of methanol, water, and glycerin areseparated from the reaction product.[180.] The present invention also provides for the method of any one ofembodiments [119]-[176], wherein the triglycerides present in thebiodiesel feedstock are transesterified with methanol, to provide areaction product including biodiesel, glycerin, water, un-reactedmethanol, and optionally un-reacted triglycerides, diglycerides, andmonoglycerides;

at least one of methanol, water, and glycerin are separated from thereaction product; and

the reaction product including biodiesel and un-reacted triglycerides,diglycerides, and monoglycerides are subsequently transesterified toprovide a subsequent reaction product including biodiesel, glycerin,water, and un-reacted methanol.

[181.] The present invention also provides for the method of any one ofembodiments [119]-[176], wherein the triglycerides present in thebiodiesel feedstock are transesterified with methanol, to provide areaction product including biodiesel, glycerin, water, un-reactedmethanol, and optionally un-reacted triglycerides, diglycerides, andmonoglycerides;

at least one of methanol, water, and glycerin are separated from thereaction product;

the reaction product including biodiesel and un-reacted triglycerides,diglycerides, and monoglycerides are subsequently transesterified toprovide a subsequent reaction product including biodiesel, glycerin,water, and un-reacted methanol; and

-   -   the separation and transesterification are optionally repeated        one or more times.        [182.] The present invention also provides for the method of        embodiment [181], the separation and transesterification are        optionally repeated one or more times until a further subsequent        reaction product does not include an appreciable or significant        amount of un-reacted triglycerides, diglycerides, and        monoglycerides.        [183.] The present invention also provides for the method of any        one of embodiments [179]-[181], wherein each of methanol, water,        and glycerin are separated from the one or more reaction        products.        [184.] The present invention also provides for the method of any        one of embodiments [179]-[181], wherein each of methanol, water,        and glycerin are separated from the reaction product and the one        or more subsequent reaction products;

the glycerin is separated from the water and methanol;

the glycerin is distilled; and

the glycerin is passed through activated carbon.

[185.] The present invention also provides for the method of embodiment[184], wherein the glycerin is distilled in a distillation column,optionally under vacuum.

[186.] The present invention also provides for the method of embodiment[185], wherein the glycerin is distilled in a distillation column, at atemperature of about 100-350° C.

[187.] The present invention also provides for the method of embodiment[185], wherein the glycerin is passed through activated carbon toeliminate impurities.

[188.] The present invention also provides for the method of embodiment[185], wherein the glycerin obtained therein has a technical grade of atleast 95 wt. % purity.

[189.] The present invention also provides for the method of any one ofembodiments [179]-[181], wherein the biodiesel is separated from thereaction product and the one or more subsequent reaction products.

[190.] The present invention also provides for the method of embodiment[189], wherein reaction product and the one or more subsequent reactionproducts include at least one of sterols, sulfur, sulfates, sulfones,sulfides, phosphorus, monoglycerides, diglycerides, and triglycerides.[191.] The present invention also provides for the method of any one ofembodiments [179]-[181], wherein the biodiesel is separated from thereaction product and the one or more subsequent reaction products, andthe biodiesel is distilled to provide purified biodiesel.[192.] The present invention also provides for the method of any one ofembodiments [179]-[191], wherein the biodiesel feedstock includingtriglycerides includes the esterification reaction product of any one ofembodiments [52]-[118].[193.] The present invention also provides for the method of any one ofembodiments [179]-[191], wherein the biodiesel feedstock includingtriglycerides includes the final distillate of any one of embodiments[1]-[51].[194.] The present invention also provides for the method of any one ofembodiments [179]-[192], wherein the transesterification reactionproduct includes biodiesel, and includes one or more of the biodieselimpurities illustrated in Table A.[195.] The present invention also provides for the method of any one ofembodiments [179]-[192], wherein the transesterification reactionproduct includes biodiesel, and includes each of the biodieselimpurities illustrated in Table A.[196.] The present invention also provides for the method of any one ofembodiments [179]-[192], wherein the transesterification reactionproduct includes biodiesel, and includes one or more of the biodieselimpurities illustrated in Table A, each in the amount disclosed therein.[197.] The present invention also provides for the method of any one ofembodiments [179]-[192], wherein the transesterification reactionproduct includes biodiesel, and includes each of the biodieselimpurities illustrated in Table A, each in the amount disclosed therein.[198.] The present invention also provides for the method of any one ofembodiments [179]-[196], wherein the transesterification reactionproduct includes glycerin, and includes one or more of the biodieselimpurities illustrated in Table A.[199.] The present invention also provides for the method of any one ofembodiments [179]-[196], wherein the transesterification reactionproduct includes glycerin, and includes each of the biodiesel impuritiesillustrated in Table A.[200.] The present invention also provides for the method of any one ofembodiments [179]-[196], wherein the transesterification reactionproduct includes glycerin, and includes one or more of the biodieselimpurities illustrated in Table A, each in the amount disclosed therein.[201.] The present invention also provides for the method of any one ofembodiments [179]-[196], wherein the transesterification reactionproduct includes glycerin, and includes each of the biodiesel impuritiesillustrated in Table A, each in the amount disclosed therein.

TABLE A Impurities PURIFIED GLYCERIN BIODIESEL (PRODUCT)^(C)FEEDSTOCK^(A) (PRODUCT)^(B) In^(D) Out^(E) Aldehydes, Ketones 30-5000ppm 2-8 ppm Anisidine value 20-90 AV 2-5 AV Ash >0.2 wt. % 0.002- 0.006wt. % Calcium 10-4,000 ppm 1-4 ppm Carboxylic acids 100-2000 ppm 1-8 ppmCarotenes (red color) 40-2,500 ppm 2-20 ppm Chloride >2,000 ppm 5-15 ppmChlorinated compounds >5,000 ppm 8-25 ppm Chlorophylls ( green color)300-1,600 ppm 4-22 ppm Cholesterol 10-6,000 ppm 4-15 ppm Cobalt 20-350ppm 2-6 ppm Cold soak N/A 20-100 Seconds Color >12 APHA <10 APHA Copper10-500 ppm 2-6 ppm Degraded proteins and 0.1-0.2 wt. % 0.001-0.005carbohydrates (brownish wt.% black color) Dicarboxylic acid 25-25,0002-7 ppm Diethylene glycol >0.2 wt. % 0.002- 0.006 wt. % Ethylene glycol0.50 wt. % 0.002- 0.006 wt. % Fatty acid and esters >0.5 wt. % ≦1 ml of0.5N NaOH consumed Free glycerin 20-100 ppm >70 wt. % by ≧95 and GC ≦101wt. % by GC Heavy metals >50 ppm ≦4 ppm Iron 20-2000 ppm 2-6 ppm Lipids0.2-0.8 wt. % 0.001%-0.0015 wt. % Magnesium 8-3000 ppm 1-6 ppm Manganese6-300 ppm 1-4 ppm Moisture 0.2-99 wt. % 10-50 ppm Nickel 5-400 ppm 1-3ppm Perchloroethylene 10-5000 ppm 2-5 ppm Peroxide value 10-300 PV 1-4PV Pesticides 0.1-2 wt. % 0.001-0.002 wt.% Phospholipids 20 ppm-30,0002-5 ppm (gums/unsaponfiables) ppm (e.g., phosphatidylcholine,phosphatidylinositol, phosphatidic acid, and lysophosphatidic acid)Phosphorus 10-4000 ppm 2-6 ppm Phytosterols 20-16,000 2-7 ppmPolychlorinated cyclic 20-6000 ppm 2-8 ppm hydrocarbons (e.g.,polychloro benzene) Polycyclic aromatic 20-6000 ppm 1-6 ppm hydrocarbonsPolyethylene 20-3000 ppm 1-7 ppm Polymerized triglycerides 0.1-6 wt. %0.001-0.002 wt.% Potassium 20-4000 ppm 2-6 ppm Sitosterols 20-3000 ppm2-8 ppm Soaps/Detergents 30-4000 ppm 1-6 ppm Sodium 10-3,500 ppm 1-5 ppmSolid particles 0.02% -30 wt. % 1-3 ppm Specific gravity @ 25° C. >0.90≧1.249 Sterol glucosides 50-2500 ppm 2-7 ppm Sulfur, sulfates, suflides,5 ppm-13,500 1-5 ppm >50 ppm 10-15 ppm sulfonates, and sulfones ppmTocopherols 8-2,650 ppm 1-5 ppm Tocotrienols 3-800 ppm 4-9 ppm Totalglycerin n/a 0.10-0.18 wt. % Triglycerides 0.001-0.01 wt. % Xantophylls(yellowish 40-1200 ppm 5-40 ppm color) Water >0.5 wt. % 0.05 wt. %- 0.20wt. % ^(A)The values and ranges illustrated herein for the Feedstock areexemplary, as the nature and amount of impurities present will typicallyvary. ^(B)The values and ranges illustrated herein for the Biodiesel areexemplary, as the nature and amount of impurities present will typicallyvary. ^(C)The values and ranges illustrated herein for the Glycerin areexemplary, as the nature and amount of impurities present will typicallyvary. ^(D)This refers to the crude glycerin obtained, prior topurification. ^(E)This refers to the pure glycerin obtained, subsequentto purification.

The invention claimed is:
 1. A method of purifying a biodieselfeedstock, the method comprising the steps in the order recited: (a)filtering a biodiesel feedstock, thereby separating from the feedstocksolid particles having a diameter up to 2 microns, to provide a filtrateand a retentate; (b) separating water from the filtrate, to provide adried filtrate; (c) distilling the dried filtrate, to provide adistillate and a residue; (d) distilling the distillate to provide asubsequent distillate and optionally a subsequent residue; and; (e)passing the subsequent distillate through an ion exchange resin toobtain a purified biodiesel feedstock; wherein the biodiesel feedstockcomprises at least one of edible oils, inedible oils, fats, greases,brown grease, trap grease, used cooking oil, used cooking fat, animalfat, animal grease, and fatty acid distillate; and wherein the followingare substantially separated from the biodiesel fuelstock in steps (a)through (e), as present; sulfur, phosphorus, gums/lipids, sterols,calcium, magnesium, iron, copper, cobalt, manganese, nickel, sodium,potassium, chlorophyll, carotenoids, xanthophylls, proteins,carbohydrates, aldehydes, ketones, carboxylic acids, perchloroethylene,polyaromatic hydrocarbons, polychlorinated hydrocarbons, polymerizedtriglycerides, pesticides, soaps, detergents, sulfonates, sulfates,phosphatides, phytosterols, sitosterols, cholesterol, and sterolglucosides.
 2. The method of claim 1, wherein the biodiesel feedstockcomprises elevated levels at least one of triglycerides, gums, soaps,detergents, unsaponifiables, phosphatides, metals, phosphorus, sulfur,sulfates, sulfonates, sulfides, polyaromatic hydrocarbons,polychlorinated hydrocarbons, polyethylene, plant based sterols, andanimal based sterols.
 3. The method of claim 1, wherein the feedstockcomprises at least about 40 wt. % free fatty acids.
 4. The method ofclaim 1, wherein at least about 90 wt. % of the solid particles having adiameter of at least about 2 microns are separated, to provide thefiltrate and the retentate.
 5. The method of claim 1, wherein theseparating of the solid particles is carried out employing multiplefilters, each having a smaller porosity or mesh size relative to aprevious filter.
 6. The method of claim 1, wherein the biodieselfeedstock comprises elevated levels of at least one of water, sulfur,phosphorus, gums/lipids, sterols, calcium, magnesium, iron, copper,cobalt, manganese, nickel, sodium, potassium, chlorophyll, carotenoids,xanthophylls, proteins and carbohydrates, aldehydes, ketones, carboxylicacids, perchloroethylene, polyaromatic hydrocarbons, polychlorinatedhydrocarbons, polymerized triglycerides, pesticides, soaps, detergents,sulfonates, sulfates, phosphatides, phytosterols, sitosterols,cholesterol, and sterol glucosides.
 7. The method of claim 1, whereinthe feedstock comprises up to about 20,000 ppm of at least one ofsulfur, sulfates, sulfides, and sulfonates.
 8. The method of claim 1,wherein the feedstock comprises up to about 4000 ppmw phosphorus.
 9. Themethod of claim 1, wherein the distilling in at least one of steps (c)and (d) is carried out under vacuum.
 10. The method of claim 1, whereinrelative to the subsequent distillate, the subsequent residue isenriched in at least one of sulfur, phosphorus, gums/lipids, sterols,calcium, magnesium, iron, copper, cobalt, manganese, nickel, sodium,potassium, chlorophyll, carotenoids, xanthophylls, proteins andcarbohydrates, aldehydes, ketones, carboxylic acids, perchloroethylene,polyaromatic hydrocarbons, polychlorinated hydrocarbons, polymerizedtriglycerides, pesticides, soaps, detergents, sulfonates, sulfates,phosphatides, phytosterols, sitosterols, cholesterol, sterol glucosides,oils, and fats.
 11. The method of claim 1, wherein relative to thesubsequent residue, the subsequent distillate is enriched in at leastone of triglycerides and free fatty acids.
 12. The method of claim 1,wherein the subsequent distillate comprises up to about 99.995 wt. %triglycerides and free fatty acids.
 13. The method of claim 1, whereinthe subsequent distillate comprises at least one of triglycerides andfree fatty acids, wherein the at least one of triglycerides and freefatty acids combined comprise less than about 7 ppm phosphorus, lessthan about 7 ppm sulfur, and less than about 10 ppm of all other metalscombined.
 14. The method of claim 1, wherein the subsequent distillatecomprises at least one of triglycerides and free fatty acids, whereinthe at least one of triglycerides and free fatty acids combined compriseless than about 7 ppm sulfur.
 15. The method of claim 1, wherein aweight of the retentate is up to about 0.2% of a weight of thefeedstock.
 16. The method of claim 1, wherein the distilling in at leastone of steps (c) and (d) comprises a multi-stage distillation column.17. The method of claim 1, wherein up to about 1,000 gallons ofbiodiesel feedstock is employed in step (a).
 18. The method of claim 1,wherein at least about 100 gallons of the purified biodiesel feedstockis obtained in step (e), within 24 hours.
 19. The method of claim 1,wherein prior to step (a), the biodiesel feedstock is analyzed todetermine a qualitative nature of impurities located therein.
 20. Themethod of claim 1, wherein prior to step (a), the biodiesel feedstock isanalyzed to determine a quantitative nature of impurities locatedtherein.
 21. The method of claim 1, wherein none of steps (a)-(e)comprise adding water.
 22. The method of claim 1, wherein the subsequentdistillate and the subsequent residue are separated.
 23. The method ofclaim 1, further comprising repeating at least one of steps (c) and (d),one or more times, by distilling the subsequent distillate, to obtain afinal distillate.
 24. The method of claim 1, wherein the feedstockcomprises at least one of tallow, pork fat, poultry fat, lard, choicewhite grease, algae oil, crude vegetable oils, soybean oil, corn oil,coffee oil, hemp oil, linseed oil, rice bran oil, jojoba oil, tall oil,mustard oil, distillers grain oil (DDG corn oil), Jatropha oil, camelliaoil, rapeseed oil, canola oil, moring a oil, pongamia oil, sunfloweroil, safflower oil, crude palm oil, palm kernel oil, palm fatty aciddistillate, palm sludge oil, and coconut oil.
 25. The method of claim 1,wherein the feedstock comprises about 0.2 wt. % to about 100 wt. % freefatty acids.
 26. The method of claim 1, wherein the purified biodieselfeedstock comprises at least one of triglycerides and free fatty acids,wherein the at least one of triglycerides and free fatty acids combinedcomprise less than about 7 ppm phosphorus, less than about 7 ppm sulfur,and less than about 10 ppm of all other metals combined.
 27. The methodof claim 1, wherein the purified biodiesel feedstock comprises at leastone of triglycerides and free fatty acids, wherein the at least one oftriglycerides and free fatty acids combined comprise less than about 7ppm sulfur.
 28. The method of claim 1, wherein the ion exchange resinincludes a straight, flow-through 2 stage guard bed column reactors inseries.
 29. The method of claim 1, wherein steps (a)-(e) are carried outin the absence of a mineral acid.